IM

S-6

   Book  of  Abstracts    

 

 

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Foreword      

On  behalf  of  the  organizing  committee  of  the  6th  International  Meeting  on  Silicene  we  

would  like  to  welcome  you  to  SOLEIL-­France.    

Silicene   is   the  silicon  analog  of  graphene,  which  has  attracted  great   interest   in   the  

past   few  years  as   it  may  provide  a  possibility   to   combine  novel   concepts,   such  as  

Dirac   fermions   and   spintronics   with   the   traditional   silicon   technology.   As   both  

theoretical  and  experimental  works  are  rapidly  increasing,  many  open  questions  still  

demand   to   be   answered.   The   “International   Meeting   on   Silicene”   is   aimed   to  

stimulate   discussions   among   researchers   in   this   growing   field,   to   establish  

collaborations  and  to  bring  more  researchers  into  the  fascinating  silicene  research.  

The   topics   of   this   meeting   will   cover   all   aspects   of   silicene,   such   as   theoretical  

predictions   and   proposals,   experimental   fabrication,   physics   and   chemistry  

properties,   measurement   of   electronic   and   optical   properties,   devices   and  

applications.  The  meeting  also  encourages  researchers  from  relative  research  fields,  

such  as  graphene  and  other  2D  materials,  to  stimulate  new  ideas  by  discussions  in  a  

broader  while  relevant  field.  

The   audience   targeted   at   this   meeting   includes   Professors,   Researchers,   and  

Engineers   from   Universities,   Engineering   Schools,   and   Research   Institutes   and  

Students.   The   conference   includes   oral   presentations   as   well   as   invited   lectures  

given  by  high  profile  scientists.    

For  this  IMS-­6,  we  warmly  thank  all  the  the  sponsors  for  their  generous  assistance.  

 

The  organizing  committee    

 

   

 

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Keynote  speaker  -­  Prof.  Noriaki  Takagi,  University  of  Tokyo,  Japan  Invited  speakers  -­  Dr.  Geoffroy  Prévot,  INP-­CNRS,  France  -­  Prof.  Laurence  MASSON  Aix-­Marseille  University,  France  -­  Prof.  Ming  Hu,  RWTH  Aachen  University,  Germany  -­  Prof.  Mustapha  Ait  Ali,  University  Cadi  Ayad,  Morocco  -­  Prof.  Laurène  Tetard,  University  of  Central  Florida,  USA,  -­  Dr.  Paolo  Moras  ,  CNR,  Sincrotrone  Trieste,  Italy  -­  Dr.  Fabio  Ronci,  CNR,  Roma,  Italy  -­  Dr.  Holger  Vach,  LPICM,  Ecole  Polytechnique,  France  -­  Prof.  Thomas  Seyller,  Technical  University  of  Chemnitz,  Germany    -­  Dr.  H.  Jamgotchian,  CINAM-­CNRS,  Marseille,  France    -­  Dr.  Guido  Fratesi,  University  of  Milan,  Italy  -­  Prof.  Salvador  Barraza-­Lopez,  Physics  Department,  University  of  Arkansas,  USA  -­  Dr.  Lenart  Dudy,  SOLEIL  Synchrotron,  France  Organizing  committee  -­  Dr.  Azzedine  BENDOUNAN,  SOlLEIL,  France  -­  Prof.  Abdelkader  KARA,  University  of  Central  Florida,  USA  -­  Prof.  Hamid  OUGHADDOU,  ISMO-­CNRS,  Cergy-­Pontoise  University,  France  Program  Committee  -­  Dr.  Bernard  Aufray,  France  -­  Dr.  Roamin  BERNARD,  France  -­  Dr.  Azzedine  BENDOUNAN,  France  -­  Dr.  Gérald  DUJARDIN,  France  -­  Dr.  Hanna  ENRIQUEZ,  France  -­  Prof.  Abdelkader  KARA,  USA  -­  Dr.  Karima  LASRI,  USA  -­  Prof.  Jean-­Louis  LEMAIRE,  France  -­  Dr.  Andrew  MAYNE,  France  -­  Prof.  Hamid  OUGHADDOU,  France  Local  Committee:  -­  Dr.  Azzedine  BENDOUNAN,  France  -­  Dr.  Hanna  ENRIQUEZ,  France  -­  Dr.  Pierre  LAGARDE,  France  -­  Prof.  Jean-­Louis  LEMAIRE,  France  -­  Dr.  Andrew  MAYNE,  France  -­  Prof.  Hamid  OUGHADDOU,  France  -­  Dr.  Yongfeng  Tong,  France  -­  Dr.  Nicolas  TRCERA,  France  

 

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SPONSORS    

 

 

     

   

 

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PROGRAM    

Wednesday,  December  13th  11:00-14:00 Registration 12:00-14:00 Lunch 14:00-14:15 Opening

Chairman: Dr. Gérald Dujardin, France 14:15-15:00 Keynote speaker: Prof. Noriaki Takagi, the University of Tokyo, Japan Exploring Of 2d Materials From Silicene To Weyl Semimental (page 8)

15:00-15h35 Invited speaker: Dr. Geoffroy Prévot, INP-CNRS, France Structure And Growth Mechanisms Of Silicene And Si Films On Ag(111) (page 9)

15:35-15:55 Oral contribution: Michal Ochapski, University of Twente, Netherlands Epitaxial Sn On H-bn Terminated ZrB2 (page 10)

15:55-16:25 Coffee Break Chairman: Prof. Laurène Tétard, USA

16:25-17:00 Invited speaker: Prof. Laurence Masson, Aix-Marseille University, France Si Nanoribbons On Ag(110): An Intriguing Epitaxial System (page 11)

17:00-17:20 Oral contribution: Peter Roese, Technische Universität Dortmund, Germany Facing The Interaction Of Absorbed Silicon Nano-ribbons On Silver (page 12)

17:20-17:55 Invited speaker: Dr. Holger Vach, LPICM, Ecole Polytechnique, France Graphite Substrates For The Formation Of Silicene And Germanene Nanosheets: Theoretical Predictions And Experimental Verifications (page 13)

18:00 Transfer to "Tour Eiffel" by Bus. Meeting point: Main entrance of SOLEIL 20:15-23:00 Conference Dinner. Meeting point: Tour Eiffel

Thursday,  December  14th  

Chairman: Dr. Bernard Aufray, France 09:00-09:35 Invited speaker: Dr. Fabio Ronci, CNR, Roma, Italy Silicene From A Chemist’s Point Of View: Definition And Stability (page 14)

09:35-10:10 Invited speaker: Dr. Paolo Moras, Istituto di Struttura della Materia – CNR, Italy Electronic Structure Of Silicene Allotropes And Multilayer Si Films On Ag(111) (page 15) 10:10-10:30 Oral contribution: Dr. Maria C. Asensio,Synchrotron SOLEIL, France “more Than Moore”: Could Silicene Be The Future Of Electronics? (page 16)

10:30-11:00 Coffee Break Chairman: Dr. Holger Vach, France

11:00-11:35 Invited speaker: Dr. H. Jamgotchian, CINAM-CNRS Marseille, France Periodic And Localized Strain Relaxation Of Silicene Layers On Ag(111) (page 17)

 

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11:35-11:55 Oral contribution: Khalid Quertite, Institut des Sciences Moléculaires d’Orsay, France Silicene Growth On Nacl Isulating Thin Films (page 18)

11:55-12:30 Invited speaker: Dr. Guido Fratesi, University of Milan, Italy Using A Buffer Layer To Tune Electron Injection Dynamics At The Organic-graphene/metal Interface (page 19) 12:30-14:30 Lunch

Chairman: Prof. Abdelilah Benyoussef, Morocco 14:30-15:05 Invited speaker: Prof. Mustapha Ait Ali, University Cadi Ayad, Morocco Chemistry Of 2d-nanomaterials: Silicene And Phosphorene (page 20)

15:05-15:40 Invited speaker: Prof. Ming Hu, Rwth, Aachen University, Germany Thermal Transport In Silicene: Counter-intuitive Phonons Beyond Graphene (page 21)

15:40-16:10 Coffee Break Chairman: Dr. Fabio Ronci, Italy

16:10-16:45 Invited speaker: Prof. Laurène Tétard, University of Central Florida, USA Functional Nanoscale Imaging Of 2d Material Properties (page 22)

16:45-17:20 Invited speaker: Prof. Salvador Barraza-Lopez, University of Arkansas, USA An Overview Of 2d Materials With Structural Degeneracies, And Consequences On Material Properties (page 23)

17:30-18:30 Poster Session (Abstracts in pages 29 to 35)

Friday,  December  15th  

Chairman: Dr. Andrew Mayne, France 09:00-09:35 Invited speaker: Prof. Thomas Seyller, Technical University of Chemnitz, Germany Epitaxial Graphene On Sic: Growth, Properties And Manipulation (page 24)

09:35-09:55 Oral contribution: Aldo Ugolotti, Universita degli Studi di Milano-Bicocca, Italy Tuning The Electronic Properties Of Silicene Through Half-hydrogenation Or Graphene Support (page 25)

09:55-10:15 Oral contribution: Prof. Nabil Rochdi, SIAM-FSSM, Cadi Ayyad University, Morocco Elaboration And Study Of Zinc And Zinc Oxide Ultrathin Layers On Silver Substrate At Room Temperature (page 26) 10:15-10:45 Coffee Break

Chairman: Prof. Salvador Barraza-Lopez, USA 10:45-11:20 Invited speaker: Dr. Lenart Dudy, SOLEIL synchrotron, TEMPO beamline, France Spectroscopy And Synthesis Of Bismuthene (page 27)

11:20-11:40 Oral contribution: Curcella Alberto, INP-CNRS, France In-situ Stm Measurements Of Si Growth On Layered Materials (page 28)

11:40-12:00 Concluding remarks 12:00-14:00 Lunch

 

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LIST  OF  ABSTACTS          

   

 

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Exploring of 2D Materials from Silicene to Weyl Semimetals Nori Takagi, Department of Advanced Materials Science, The University of Tokyo E-mail : n-takagi@k.u-tokyo.ac.jp Abstract: Triggered by the discovery of graphene, two-dimensional (2D) materials such as silicene, germanene and transition metal dichalcogenides (TMDCs) are in the spotlight from fundamental and technological points of view. Recently, silicene on Ag(111) and Ag(110) has been investigated intensively and the geometric and electronic structures have been established [1-5]. TMDCs take various geometric structures and the electronic structures vary from semiconductor to semimetal and metal. MoTe2 and WTe2 are unique among the family of TMDCs, because these TMDCs host Weyl fermions long sought in high energy particle physics. The electron and hole pockets cross and the low-energy excitations around the crossing points (called as Weyl points) are well described by Weyl equation. Here I present a brief review about silicene on Ag(111) and Ag(110) substrates at first and then demonstrate the electronic structures of WTe2 and MoTe2, especially the locations of Weyl points and their connections with the topological Fermi arc surface states based on the quasiparticle interference measurements with a low-temperature STM together with DFT calculations [6]. References: [1] Takagi, N. et al., (2015). Silicene on Ag(111): geometric and electronic structures of a new honeycomb material of Si. Progress in Surface Science 90, 1-20. [2] Oughaddou, H. et al., (2015). Silicene, a promising new 2D material, Progress in Surface Science 90, 46-83. [3] Houssa, M., Dimoulas, A. and Molle, A. (2015). Silicene: a review of recent experimental and theoretical investigations. Journal of Physics: Condensed Matter 27, 253002. [4] Spencer, M. J. S. and Morishita, T. (Eds) (2016). Silicene –Structure, Properties and Applications, Switzerland: Springer. [5] Cahangirov, S. et al., (2017). Introduction to the Physics of Silicene and Other 2D Materials. Switzerland: Springer. [6] Lin, C.-L. et al., (2017) Visualizing Type-II Weyl Points in Tungsten Ditelluride by Quasiparticle Interference, Acs Nano DOI: 10.1021/acsnano.7b06179. Contribution: Keynote

 

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Structure and Growth Mechanisms of Silicene and Si films on Ag(111)† G. Prévot1, A. Curcella1, R. Bernard1, Y. Borensztein1, M. Lazzeri2, Y. Garreau,3 A. Resta3 1Institut des Nanosciences de Paris, CNRS UMR 7588 and UPMC, Paris, France 2IMPMC, UMR CNRS 7590, MNHN, IRD UMR 206 and UPMC, Paris, France 3 Synchrotron SOLEIL, Gif-sur-Yvette, France

E-mail :prevot@insp.jussieu.fr Abstract:

The synthesis of two-dimensional silicon films that would display electronic properties analog to those of graphene attracts today a considerable interest, in particular for applications in microelectronics. Since the theoretical prediction of the metastability of free-standing silicene, a buckled hexagonal Si plane presenting a Dirac cone in its electronic structure, silicene layers have been claimed to grow on various substrates such as MoS2, ZrB2, graphite or Ir(111). Up to now, most of the studies have been performed on Ag(111) substrates where hexagonal structures presenting electronic band structure expected from silicene have been deduced from scanning tunneling microscopy (STM) and photoemission (ARPES) experiments.

Using STM, grazing incidence X-ray diffraction, and density functional theory calculations (DFT), we have real-time followed up the growth of silicene monolayers and multilayers on Ag(111) and elucidated the structure of several phases. Whereas the silicene single layers grown on Ag(111) truly correspond to hexagonal buckled planes, the so-called silicene multilayers are in fact bulk diamond-like silicon thin films.

We also evidenced an unexpected growth mechanism. During Si deposition, Ag atoms are expelled from the substrate, leading to the formation of inserted Si domains on Ag(111). After the completion of the silicene layer, further growth leads to the formation of thick Si islands that insert deeper in the Ag substrate. During their formation, Ag atoms are expelled. Nearly half of them form the honeycomb chain triangle Ag/Si structure on top of the islands, the other half intercalate between the remaining single silicene layer and the substrate, as evidenced by STM. This is the signature of an unforeseen "surfacting competition" between Ag and silicene: the silver surface remains covered by silicene during this additional Ag growth, and the surface of Si islands remains covered by Ag atoms during Si growth. DFT results explain the extreme stability of the silicene monolayer. † R. Bernard et al., Phys. Rev. B 88 (2013) 121411(R) Y. Borensztein, G. Prévot, L. Masson, Phys. Rev. B 89 (2014) 245410 G. Prévot et al., Appl. Phys. Lett. 105 (2014) 213106 R. Bernard et al., Phys. Rev. B 92 (2015) 045415 Y. Borensztein et al., Phys. Rev. B 92 (2015) 155407 A. Curcella et al., Phys. Rev. B 94 (2016) 165438 G. Prévot et al., Phys. Rev. Lett. 117 (2016) 276102 A. Curcella et al., 2D Materials 4 (2017) 025067 Contribution: Invited

 

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Epitaxial Sn on h-BN terminated ZrB2 MICHAL OCHAPSKI, FRANK WIGGERS, MICHEL DE JONG MESA+ Institute, NanoElectronics Group, University of Twente E-mail : m.w.ochapski@utwente.nl Abstract: Stanene, the tin analogue of graphene, is a 2-dimensional (2D) Dirac material that promises a wealth of physical phenomena [1-6] and bright perspectives for electronic applications. Free-standing stanene is predicted to feature Dirac fermions near the Fermi energy just like its carbon counterpart. Spin-orbit coupling may be much larger than in graphene, silicone or germanene, such that it could support a large-gap 2D quantum spin Hall (QSH) state, and thus enable the dissipationless electric conduction at room temperature[1-3]. It could also provide enhanced thermoelectricity [4], topological superconductivity [5], and the near-room-temperature quantum anomalous Hall (QAH) effect [6]. In spite of these promising properties predicted theoretically, the synthesis of (free-standing) stanene still remains a major challenge. So far there is only one report of epitaxialy grown stanene [7]. The electronic structure differs considerably from the theoretically predicted electronic properties of free standing stanene, because of the interaction with the substrate. Moreover, further discrepancies between the experimentally observed band structure and theory were attributed by the authors to unintentional hydrogenation of the stanene. The chemical sensitivity of stanene forms a complexity in its synthesis, but could also allow for engineering of its electronic properties. Recently, we found that, after Sn deposition on silicene- and h-BN terminated ZrB2(1111) epitaxial thin films on Si(111) wafers, we could observe various new surface reconstructions, attributed to Sn, in LEED pictures of both samples. Preliminary APRES measurements show new metallic bands, however due to the heterogeneous character of the surface (observed by PES and LEED) after Sn deposition, these could only be observed on a small part of the sample. Various different ordered Sn-phases are to be expected, based on previous PES and LEED results, with presumably different band structure. Exploration of these Sn layers could contribute strongly to stanene research. References: [1] Xu.et al. PRL 111,136804 (2013). [2] Liu et al. PRB 84, 195430 (2011). [3] Zhang et al. PRB 90, 075114 (2014). [4] Xu et al. PRL 112, 226801 (2014). [5] Wang et al. PRB 90, 054503 (2014). [6] Wu et al PRL 113, 256401 (2014). [7] Zhu F et al. Nat. Mater. 14 1020 (2015) Contribution: Oral

 

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Si  nanoribbons  on  Ag(110):  an  intriguing  epitaxial  system    Laurence  Masson  

CINaM,     Aix-­Marseille   Université,   CNRS,   Campus   de   Luminy,   Case   913,   13288   Marseille,   France Abstract: Since the discovery in 2005 of the synthesis of Si nanoribbons (NRs) on Ag(110) upon Si deposition at room temperature (RT), a long debate concerning the atomic structure of these NRs began after the reported graphene-like electronic signature measured by angle-resolved photoelectron spectroscopy (ARPES) [1] and attributed to the silicene character of the Si NRs. Si NRs with a width of 0.8 nm are randomly distributed on silver terraces or self-assembled in a (5x2) unit cell to form a 2D single-atom-thick Si layer composed of regularly spaced NRs with a width of 1.6 nm, for Si deposition at RT and 460 K, respectively. Our first contribution to solve the atomic structure of the Si NRs was to provide compelling evidence, by a combined scanning tunneling microscopy-grazing incidence x-ray diffraction (STM-GIXD) study, of an unexpected Ag(110) missing row surface reconstruction associated with the release of Ag atoms induced by the Si NR growth [2]. Recently, we published a combined theoretical (density-functional theory (DFT) calculations) and experimental (STM, GIXD) study [3] which definitively elucidates the atomic structure of the Si NRs, among the numerous models proposed in the literature [4]. The Si NRs correspond to an original Si phase composed of pentamer chains lying in the missing rows of the reconstructed surface (see Fig. below). In this talk, it will also be shown that the strong Si-Ag interaction has to be taken into account to interpret the optical properties of the Si/Ag interface [5]. Finally, apart from these investigations, it will be presented recent results showing that 2D Si layers on Ag(110) can be advantageously used as a template for the self-organized growth of 3d metal nanolines exhibiting magnetic properties [6].  This  work  on  the  Si/Ag(110)  interface  is  issued  from  a  collaboration  between  CINaM-­Marseille,  INSP-­Paris  and  CNR-­ISM-­Rome.    

 

 

Figure  :  a)  STM  image  (77  K)  of  Si  nanoribbons  (NRs)  below  completion   of   the  Si  monolayer.   I   =   480   pA,  Vsample=   40  mV.  The  atomic   rows  of  Ag(110)  are  visible.   b)   Schematic  model  of  a  Si  NR  on  the  missing  row  reconstructed  Ag(110)  surface  and  the  corresponding  simulated  STM  image.  

 

References    

[1]  P.  De  Padova,  C.  Quaresima,  C.  Ottaviani,  P.  M.  Sheverdyaeva,  P.  Moras,  C.  Carbone,  D.  Topwal,  B.  Olivieri,  A.  Kara,  H.  Oughaddou,  B.  Aufray,  G.  Le  Lay,  Appl.  Phys.  Lett.  96,  261905  (2010).  [2]  R.  Bernard,  T.  Leoni,  A.  Wilson,  T.  Lelaidier,  H.  Sahaf,  E.  Moyen,  L.  Assaud,  L.  Santinacci,  F.  Leroy,  F.  Cheynis,  A.  Ranguis,  H.  Jamgotchian,  C.  Becker,  Y.  Borensztein,  M.  Hanbücken,  G.  Prévot,  L.  Masson,  Phys.  Rev.  B  88,  121411(R)  (2013).  [3]  G.  Prévot,  C.  Hogan,  T.  Leoni,  R.  Bernard,  E.  Moyen,  L.  Masson,  Phys.  Rev.  Lett.  117,  276102  (2016).  [4]  J.  I.  Cerdá,  J.  Sławińska,  G.  Le  Lay,  A.  C.  Marele,  J.  M.  Gómez-­Rodríguez,  M.  E.  Dávila,  Nat.  Commun.  7,  13076  (2016).  [5]  Y.  Borensztein,  G.  Prévot,  L.  Masson,  Phys.  Rev.  B  89,  245410  (2014).  [6]  L.  Michez,  K.  Chen,  F.  Cheynis,  F.  Leroy,  A.  Ranguis,  H.  Jamgotchian,  M.  Hanbücken,  L.  Masson,  Beilstein  J.  Nanotechnol.  6,  777  (2015). Invited  

 

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Facing the Interaction of Absorbed Silicon Nano-Ribbons on Silver Peter Roese(a,b), Philipp Espeter(a,b), Karim Shamout(a,b), Ulf Berges(a,b), Carsten Westphal(a,b) (a) Experimentelle Physik 1, Technische Universität Dortmund, Germany (b) DELTA, Technische Universität Dortmund, Germany Corresponding author: Peter Roese, E-mail : peter.roese@tu-dortmund.de Abstract: For the formation of one-dimensional silicon nano-ribbons on a Ag(110) surface many different structure models have been reported in the last years [1-9]. The range of proposed structures includes rectangular, hexagonal, planar, stacked and pentagonal formation of silicon atoms as well as different reconstructions of the substrate beneath. Knowledge about the exact structure of silicon nano-ribbons is of great importance for the determination of electronic properties and also for possible applications in nano-technological [10] and electronic devices built by nano-ribbons [4, 11]. At the moment, silicon nano-ribbons have only been prepared on metallic surfaces, but in the context of fabrication of electronic devices, a transfer of the nano-ribbons from the metallic surface to an insulator needs to be realized. Due to that, a complete understanding of the interaction between the nano-ribbons and the substrate is necessary. In the last few years the analysis of the interfacial properties and bonding was neglected. Here we will discuss on the one hand the exact structure of silicon nano-ribbons on Ag(110) based on the different proposed structure models mentioned before, and on the other hand the interaction between nano-ribbons and substrate by using the surface- and interface-sensitive method photoelectron diffraction (XPD). Our results reveal a weak interaction of silicon nano-ribbons with the underlying silver substrate identifying the specific locations of the individual silicon and silver atoms. Further, we show the unique experimental evidence that clarifies the origin of the two distinct chemically shifted components in the silicon photoelectron spectra. [1] Vogt et al., Phys. Rev. Lett. 108, 155501 (2012) [2] He et al., Phys. Rev. B 73, 035311 (2006) [3] Leandri et al., Surf. Sci. 574, L9 (2005) [4] Cerdá et al., Nat. Commun. 7, 13076 (2016) [5] Prévot et al., Phys. Rev. Lett. 117, 276102 (2016) [6] Aufray et al., Appl. Phys. Lett. 96, 183102 (2010) [7] Feng et al., Surf. Sci. 645, 74 (2016) [8] Sahaf et al., Appl. Phys. Lett. 90, 263110 (2007) [9] Bernard et al., Phys. Rev. B 88, 121411 (2013) [10] Dávila et al., Nanotechnology 23, 385703 (2012) [11] Salomon et al., Surf. Sci. 602, L79 (2008) Contribution: Oral

 

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Graphite substrates for the formation of silicene and germanene nanosheets: theoretical predictions and experimental verifications

Holger VACH, LPICM, Ecole Polytechnique, Palaiseau, France E-mail : holger.vach@polytechnique.edu Abstract: Our economy consistently pushes for the development of revolutionary materials to meet our ever-increasing technological demands. In this context, we have undertaken in-depth theoretical and experimental studies on the growth of a new allotropic form of silicon and germanium: namely silicene and germanene. In order to rule out any intermixing between Si or Ge atoms and the underneath substrate atoms, as it was the case for some metallic substrates and was confirmed by our molecular dynamics simulations, and to maintain their promising features to be new Dirac materials, we have performed our deposition on chemically inert graphite substrates (HOPG). Several silicene and germanene areas are obtained by the deposition of Si and Ge on HOPG substrates at room temperature and under ultrahigh vacuum conditions. One of our crucial findings is that the silicene and germanene monolayers interact with the graphite substrate via van der Waals forces only. Atomic force microscopy and scanning tunneling microscopy images support the formation of quasi-continuous 2D silicon and germanium layers with small buckling, leaving some areas of the HOPG substrate uncovered together with the formation of small 3D Si and Ge clusters. Our ab initio molecular dynamics simulations predict thermal stability of a perfect silicene monolayer on HOPG up to a surface temperature of about 350 ºC highlighting the essential role of van der Waals forces bonding silicene or germanene to the surface. The van der Waals interaction is strong enough to stabilize the deposited monolayers even above room temperature, but weak enough to prevent any alloying of Si or Ge atoms with C atoms. Consequently, the outstanding electronic properties of silicene and germanene, such as Dirac cones, are preserved even after their deposition on the graphite surface. The simulation of the growth mechanism of the silicene sheet on HOPG at room temperature shows how silicon hexagons spontaneously form and remain at a vertical distance corresponding to the van der Waals distance above the surface. The main problem of previously observed high-buckled silicene is its strong oxidation that occurs when exposed to air. In our work, we demonstrate that the use of highly oriented graphite substrates leads to air-stable low-buckled silicene nanosheets. This conclusion derives from the excellent agreement between the experimental observation and ab initio calculations of the corresponding Raman peak located at 542.5 cm-1 which is completely different from the one measured for silicene grown on Ag(111) surfaces. We are confident that in the future by using more sophisticated growth methods, larger areas of these ultrathin films can be obtained which can be detached and transferred for device applications. References: M. De Crescenzi et al., ACS Nano 10 11163−11171 (2016). L. Persichetti et al., J. Physical Chemistry Letters, 7 (16), 3246-3251 (2016). Contribution: Invited

 

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Silicene from a chemist’s point of view: definition and stability F. RONCI, Istituto di Struttura della Materia-CNR (ISM-CNR) Rome, Italy E-mail : ronci@ism.cnr.it Abstract: Silicene, the 2D silicon allotrope analogue of graphene, was theoretically predicted in 1994 as a stable freestanding buckled honeycomb silicon monolayer with electronic structure hosting, similarly to graphene, Dirac cones. In the last decade several papers reported the synthesis of silicene on Ag(110) and Ag(111) substrates, attracting a large interest in the scientific community. However, recent results questioned the two main pillars on which the claim of silicene realization was based, namely i) the attribution to the Dirac cones signature of the linearly dispersive band observed by angle resolved photoemission spectroscopy near the Fermi level and ii) the weak interaction between Si and the Ag substrate that would consent silicene growth without Si/Ag reaction. In the first part of my talk I will reconsider the silicene topic starting from the point of view of the chemistry of unsaturated silicon compounds, discussing the approach used for synthesizing such unstable compounds and comparing them to silicene. In the last part, I will survey our recent years results on both the Si/Ag(110) and Si/Ag(111) systems, showing in particular that such silver substrates are not inert toward silicon. Contribution: Invited

 

15

Electronic structure of silicene allotropes and multilayer Si films on Ag(111) P. MORAS, Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Trieste, Italy E-mail : paolo.moras@ism.cnr.it Abstract: The fascinating electronic properties of graphene have led to the exploration of other single-element 2D materials with honeycomb-like structure. Silicene is expected to display, in the free-standing form, significant analogies to graphene due to the presence of Dirac cones near the Fermi level and additional spin-orbit-related topological properties. Its synthesis on solid surfaces, however, poses questions on the preservation of the 2D character of the electronic states. In this talk I will present an angle-resolved photoemission spectroscopy analysis of Si on Ag(111). Below the completion of the first monolayer Si forms different honeycomb-like allotropic phases on this substrate. For all phases symmetry-selective hybridization with the Ag sp-states destroys the π-derived Dirac cone features near the Fermi level, while σ-derived bands at deeper energies are weakly affected by the substrate [1-3]. In agreement with the results of structural studies, multilayer Si films on Ag(111) display electronic states similar to those of bulk Si(111) with a 3× 3-Ag surface termination [4,5]. The absence of Dirac cones in monolayer silicene as well as in multilayer Si films on Ag(111) makes the analogy with the 2D electronic structure of graphene inappropriate. [1] P. Moras, T. O. Mentes, P. M. Sheverdyaeva, A. Locatelli, and C. Carbone, J. Phys.: Condens. Matter 26,

185001 (2014). [2] S. K. Mahatha, P. Moras, V. Bellini, P. M. Sheverdyaeva, C. Struzzi, L. Petaccia, and C. Carbone, Phys. Rev.

B 89, 201416(R) (2014). [3] P. M. Sheverdyaeva, S. Kr. Mahatha, P. Moras, L. Petaccia, G. Fratesi, G. Onida, and C. Carbone, ACS

Nano 11, 975 (2017). [4] S. K. Mahatha, P. Moras, P. M. Sheverdyaeva, R. Flammini, K. Horn, and C. Carbone, Phys. Rev. B 92,

245127 (2015). [5] S. K. Mahatha, P. Moras, P. M. Sheverdyaeva, V. Bellini, T. O. Menteş, A. Locatelli, R. Flammini, K. Horn,

and C. Carbone, J. Electron. Spectrosc. Relat. Phenom. 219, 2 (2017). Contribution: Invited

 

16

“More than Moore”: Could silicene be the future of electronics?

José Avila1, Seymur Cahangirov2,3, Angel Rubio2 and Maria C. Asensio1

1Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin-BP 48, 91192 Gif sur Yvette Cedex, France 2Nano-Bio Spectroscopy Group and ETSF Scientific Development Centre, Departamento de Física de Materiales, Universidad del País Vasco, CSIC-UPV/EHU-MPC and DIPC, Avenida de Tolosa 72, E-20018 San Sebastian, Spain 3Institute of Material Science and Nanotechnology, Bilkent University, Ankara 06800, Turkey E-mail: asensio@synchrotron-soleil.fr Abstract: Finding novel materials with smart properties is one of the major challenges of material science research activity. In particular, the electronics market demand for increased performance cannot be met anymore with conventional packaging and interconnect technologies. Consequently, the technology roadmap for semiconductors or Moore’s Law, which states that the number of components integrated in a circuit would increase exponentially over time, should be replaced by a more effective approach regarded as “More than Moore” 1. This new trend adds value to devices by incorporating new functionalities, which do not necessarily scale according to “Moore's Law”. A close relative of graphene, a 2D honeycomb lattice of Si atoms called Silicene has been recently reported as nanoribbons and single layers on silver monocrystals, oriented (111)2-4. Silicene has been theoretically predicted as a buckled honeycomb arrangement of Si atoms and having an electronic dispersion resembling that of relativistic Dirac fermions5. In this presentation we will show, (for the first time to our knowledge) compelling evidence, from both structural and electronic properties of silicene and its evolution as a function of silicon layers till develop a complete silicon 3D single crystal on silver single crystals. We have combined high energy and momentum resolution synchrotron radiation angle-resolved photoemission spectroscopy to fully characterize the main electronic structure characteristics of this new exciting material. References:

(1)  “More than Moore”, see the Weblink: http://www.itrs.net/news.html (2)   P. Vogt, P. De Padova, C. Quaresima, J. Avila, E. Frantzeskakis, M.C. Asensio, A. Resta, B. Ealet, and

G. Le Lay, Phys. Rev. Lett. 108, 155501 (2012) (3)   P. De Padova et al., Appl. Phys. Lett. 96, 261905 (2010) (4)   S.S. Cahangirov, M. Topsakal, E. Aktürk, H. Sahin and S. Ciraci, Phys. Rev. Lett. 102, 236804 (2009). (5)  S.Cahangirov, V. Ongun Özçelik, L. Xian, J. Avila, S. Cho, M. C. Asensio, S. Ciraci,

and A. Rubio Phys. Rev. B 90, 035448 (2014) Contribution: Oral

 

17

Periodic and localized strain relaxation of silicene layers on Ag(111) H. JAMGOTCHIAN, B. EALET, JP. BIBERIAN and B. AUFRAY, Aix-Marseille Université, CNRS, CINaM, UMR 7325, 13288 Marseille, France E-mail : jamgotchian@cinam.univ-mrs.fr Abstract: The growth of a silicene layer on Ag(111) gives rise to different superstructures depending of the substrate temperature. From about 150°C to 300°C and above one observes successively a quasi-pure 4x4 superstructure then a mix of (4x4), (√13x√13)R19.1° and (2√3x2√3)R30° superstructures and finally a quasi-pure (2√3x2√3)R30°superrstructure. All these superstructures are related to a quasi-perfect match between the silicene layer and the Ag substrate (-0.3% , -2.5% and +1.5% respectively). They have been precisely characterized by STM-LEED and confirmed by DFT calculations. More recently the large Moiré patterns observed by STM at low magnification on large areas on both (2√3x2√3)R30° and (√13x√13)R19.1° superstructures have been interpreted via a periodic relaxation of the epitaxial strain localized around perfect domains. In this presentation we will show that the same approach can be used for the 4x4 and that the “new” phase reported in different studies is more likely a local relaxation of the epitaxial strain. Ball model proposed is in very good agreement with STM image observations. Contribution: Invited

 

18

Silicene Growth On NaCl Thin Films Khalid Quertite1,3,4, Karima Lasri2, Hanna Enriquez1, Andrew J. Mayne1, Abdelkader Kara2, Azzedine Bendounan3, Pierre Lagarde3, Gérald Dujardin1, and Nicolas Trcera3, Abdallah El kenz4, Abdelilah Benyoussef4,5 and Hamid Oughaddou1,6

1Institut des Sciences Moléculaires d’Orsay, ISMO-CNRS, Bât. 210, Université Paris-Sud, 91405 Orsay, France 2Department of Physics, University of Central Florida, Orlando, FL 32816, USA 3Synchrotron Soleil, L’Orme des Merisiers Saint-Aubin, B.P. 48, 91192 Gif-sur-Yvette Cedex, France 4LMPHE, Faculté des Sciences, Université Mohammed V - Agdal, Rabat, Morocco 5Institute of Nanomaterials and Nanotechnology, MAScIR, Rabat, Morocco 6Département de Physique, Université de Cergy-Pontoise, 95031 Cergy-Pontoise Cedex, France Abstract : Silicene the silicon based analog of graphene has a 2D structure that could have some attractive electronic properties: massless Dirac fermions, high electron mobility… It is a particularly promising material for nanotechnology because it can be integrated into industry-based silicon electronics. The existence of silicene has been achieved recently by epitaxial growth of silicon on the noble metal substrate Ag and Au. However, the electronic interaction between silicene and the metallic substrates is strong and could mask its electronic properties. In order to access the intrinsic properties of silicene we plan to grow silicene on an insulating material such as NaCl. We have grown thin film of NaCl (1 ML) on Ag(110) surface. The STM images show that NaCl film presents a large and defect free area and presents a (4x1) superstructure. The Theoretical calculations (DFT) of NaCl on Ag(110) substrate support the experimental observations already found. Deposition of silicon atoms on NaCl induces a (4x3) superstructure and the STM images show that silicon forms a silicene sheet with a honeycomb like structure. In order to get access to the silicene electronic structure, experiments using Synchrotron facilities at SOLEIL such as EXAFS and ARPES techniques are programmed in LUCIA and TEMPO beam-lines.

Contribution: Oral

 

19

Using a buffer layer to tune electron injection dynamics at the organic-graphene/metal interface

A. RAVIKUMAR1, G. KLADNIK2, M. MULLER3, A. COSSARO4, G. BAVDEK5, L. PATERA6, D. SANCHEZ PORTAL3, L. VENKATARAMAN7, A. MORGANTE4,6, G. P. BRIVIO1, D. CVETKO2,4, G. FRATESI8 1Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Milano, Italy 2Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia 3Centro de Fisica de Materiales, San Sebastian, Spain 4CNR-IOM, Laboratorio TASC, Trieste, Italy 5Faculty of Education, University of Ljubljana, Ljubljana, Slovenia 6Dipartimento di Fisica, Università di Trieste, Trieste, Italy 7Department of Chemistry, Columbia University, NY 8Dipartimento di Fisica, Università degli Studi di Milano, Milano, Italy E-mail: guido.fratesi@unimi.it Abstract: The properties of novel and prospective 2D materials are dramatically influenced by the interaction with a substrate. For example, the electronic hybridization of silicene states on Ag(111) or graphene ones on Ni(111) disrupts the Dirac fermions of the freestanding layers. This calls for efficient approaches to tune the interaction strength at the interface. Here we focus on the case of graphene functionalized by organic molecules and grown on Ni(111) and on the interfacial charge transfer dynamics. This is investigated by X-ray resonant photoemission spectroscopy, that is able to measure electron transfer rates occurring within few femtoseconds, and by a theoretical framework based on density-functional theory [1,2].

We use 4,4’-bipyridine as the prototypical molecule for these explorations as the energy level alignment of core-excited molecular orbitals allows ultrafast injection (τ=4fs) of electrons from the substrate to the molecule adsorbed on epitaxial graphene/Ni(111), which is characterized by a strong hybridization between C and

metal states. We demonstrate that this interface can be decoupled by the addition of a second layer of graphene, where the one in contact with the metal acts as a buffer layer and the one in contact with the molecule is less hybridized with Ni underneath. This decreases the charge transfer rates by about one order of magnitude and is seen in both theory and experiments. [1] G. Fratesi, C. Motta, M. I. Trioni, G. P. Brivio, and D. Sánchez-Portal, J. Phys. Chem. C 118 (2014) 8775 [2] D. Cvetko, G. Fratesi, G. Kladnik, A. Cossaro, G.P. Brivio, L. Venkataraman, and A. Morgante, Phys. Chem. Chem. Phys. 18 (2016) 22140 Contribution: Invited

 

20

Chemistry of 2D-nanomaterials: Silicene and phosphorene

Mustapha Ait Ali, Laboratoire de Chimie de Coordination et Catalyse, Département de Chimie, Faculté des Sciences-Semlalia, Université Cadi Ayyad, Marrakech, 40001, Morocco E-mail:aitali@uca.ac.ma Abstract:

 

2D materials are atomically thin sheets that exhibit unique electronic, optical and mechanical properties with remarkable potential for technological applications and a plethora of unexplored fundamental science. For example, graphene is the prototypical 2D material, exhibiting high charge carrier mobilities, chemical inertness and high mechanical strength. Although many bulk materials exhibit layered structures with quasi-2D characteristics, 2D materials are defined here as those composed of one to several (generally, 10 or less) discrete, atomically thin layers that are weakly interacting, often through van der Waals forces. The superlative physical properties of 2D materials arise from the intrinsic chemical properties of their constituent elements, which are incorporated into covalently bonded structures of particular symmetry and low (that is, 2D) dimensionality. The chemically simplest cases exist in elemental 2D materials, of which two are known to also occur in bulk layered form: graphene and recently: silicene and phosphorene. Since facile fabrication processes of large area nanosheets are required for practical applications, a development of soft chemical synthesis route without using conventional vacuum processes is a challenging issue. Techniques for the exfoliation of layered compounds are widely used to fabricate nanometer-thick materials, such as oxides, niobates, chalcogenides, phosphates, and graphene. Although a variety of nanosheets have been synthesized, there have been few reports of silicon and phosphor nanosheets. Mass production of silicon and phosphor nanosheets without conventional vacuum processes and vapor deposition can be achieved using low cost top-down approach starting from materials that comprise a 2D sheet structure as a fundamental unit. Chemical processes provide an alternative route to large-scale synthesis of 2D nanomaterials under production conditions. In this perspective, this work focuses on recent progress in chemistry of 2D-nanomaterials:

ü   silicene, ü   phosphorene.

  Contribution: Invited

 

21

Thermal Transport in Silicene: Counter-intuitive Phonons beyond Graphene† M. Hu Institute of Mineral Engineering, Division of Materials Science and Engineering, Faculty of Georesources and Materials Engineering, RWTH Aachen University, Germany E-mail : hum@ghi.rwth-aachen.de Abstract: Silicene — the silicon counterpart of graphene — has a two-dimensional structure that leads to a host of fascinating physical and chemical properties of significant utility. Despite the similar electrical property of silicene compared to graphene, such as Dirac fermions, little research has been explicitly devoted to the thermal (phonon) transport of silicene so far. In fact, thermal transport property of silicene is distinctively different from the analogy graphene in many aspects, which represents an efficient way of optimizing performances of silicene relevant devices. In this talk, I will mainly present how the thermal transport in silicene is different form graphene under different conditions. First, unlike the commonly believed understanding that thermal conductivity only decreases with increased tensile strain for graphene, it is found that the thermal conductivity of silicene can increase dramatically with strain. Such unusual enhancement plausibly originates from the flattening of the buckling of the silicene structure upon stretching, which is unique for silicene as compared with other common two-dimensional materials. Second, we observe a counter-intuitive phenomenon that, the thermal conductivity of silicene can be either enhanced or suppressed by changing the surface crystal plane of the substrate. This phenomenon is fundamentally different from the general understanding of supported graphene, in which the substrate always has a negative effect on the phonon transport of graphene. The dramatic increase in the thermal conductivity of silicene supported on the 6H-SiC substrate is due to the augmented lifetime of the majority of the acoustic phonons. Third, motivated by the inherent relationship between phonon behavior and interatomic electrostatic interaction, we demonstrate that by applying an electric field the thermal conductivity of silicene can be reduced to a record low value of 0.09 W/mK, which is more than two orders of magnitude lower than that without an electric field (19.21 W/mK) and is even comparable to that of the best thermal insulation materials. Fundamental insights are gained from observing the electronic structures. Our study paves the way for robustly tuning phonon transport in materials without altering the atomic structure, and would have significant impact on emerging applications, such as thermal management, nanoelectronics and thermoelectrics. References: †Hu M, Zhang X & Poulikakos D (PRB) 2013.

Zhang X, Xie H, Hu M; Bao H, Yue SY, Qin G & Su G (PRB) 2014. Xie H, Hu M & Bao H (APL) 2014. Xie H, Ouyang T, Germaneau E, Qin G, Hu M & Bao H (PRB) 2016. Zhang X, Bao H & Hu M (Nanoscale) 2015. Qin G, Qin Z, Yue SY, Yan QB & Hu M (Nanoscale) 2017.

Contribution: Invited

 

22

Functional nanoscale imaging of 2D material properties

Yi Ding, Laurene Tetard NanoScience Technology Center, Material Science Engineering Department,

Physics Department, University of Central Florida, Orlando, FL  

Two-dimensional (2D) materials constitute elegant systems to explore fundamental processes in condensed matter. However, the dimensions of the samples, both in thickness and laterally - can make excitation or probing difficult. This becomes all the more challenging when exploring dynamic phenomena in 2D structures. Hence, the growing interest in this field calls for the development of spectroscopy and imaging approaches suitable for sensitive measurements of opto-electronic or functional phenomena. In this talk, we will discuss how infrared spectroscopy and functional atomic force microscopy (AFM) measurements can be used to study 2D materials including MoS2 systems in which the electronic properties have been manipulated. We will also present some examples of how characterization can support the design of Van der Waals heterostructures. Lastly, we will present our work focusing on the mechanisms of catalytic activation using 2D metal-free materials such as hexagonal boron nitride (h-BN). More specifically, we will discuss how defects such as vacancies and dopants play a critical role in modifying the electronic and chemical properties of 2D materials to offer catalytically active sites, such as for the conversion of synthetic gases into higher alcohols. We will discuss various means to introduce defects in 2D materials and we will compare the characteristics of the features formed in the material as a result of the material treatment. In particular, we will discuss changes in structure, chemical signatures, mechanical properties and charge distribution. Finally, we will discuss how nanoscale functional imaging can deepen our understanding of how these defects participate in the catalytic process from a molecular point of view. Contribution: Invited

 

23

An overview of 2D materials with structural degeneracies, and consequences on material properties

Salvador Barraza-Lopez

Associate Professor. Department of Physics. University of Arkansas

sbarraza@uark.edu

I will introduce the basic physical consequences of reduced structural symmetries on 2D materials beyond graphene [1-2] including silicene [3]: structural reduced symmetries are prominent in 2D materials, and these reduced symmetries lead to two-dimensional structural (i.e., non-topological) phase transitions [1-4] and to additional exotic behavior. References: [1] M. Mehboudi, A.M. Dorio, W. Zhu, A. van der Zande, H.O.H. Churchill, A.A. Pacheco-Sanjuan, E.O. Harriss, P. Kumar, and S. Barraza-Lopez. Nano Lett. 16, 1704 (2016) [2] M. Mehboudi, B. M. Fregoso, Y. Yang, W. Zhu, A. van der Zande, J. Ferrer, L. Bellaiche, P. Kumar, and S. Barraza-Lopez. PRL 117, 246802 (2016) [3] G. G. Naumis, S. Barraza-Lopez, M. Oliva-Leyva, and H. Terrones. Rep. Prog. Phys. 80, 096501 (2017) [4] K. Chang, et al. Science 353 274 (2016) [5] R. Haleoot, C. Paillard, M. Mehboudi, B. Xu, L. Bellaiche, and S. Barraza-Lopez. PRL 118, 227401 (2017) Contribution: Invited

 

24

Epitaxial Graphene on SiC: Growth, Properties and Manipulation

THOMAS SEYLLER, TU Chemnitz, Institut für Physik, Reichenhainer Str. 70, 09126 Chemnitz, Germany E-mail : thomas.seyller@physik.tu-chemnitz.de Abstract: More than ten years ago, ground-breaking experimental studies of graphene – a monolayer of carbon with honeycomb structure – were reported [1]. Charge carriers in graphene are described by the Weyl-Hamiltonian for massless particles, resulting in interesting properties such as an unusual quantum Hall effect [1] or Klein tunneling [2] which sparked the interest of scientists around the world. The charge carriers in graphene are characterized by a high mobility, which makes graphene interesting for electronic applications such as high frequency transistors [3] and frequency mixers [4]. Furthermore, graphene is mechanically very stable but also flexible and at the same time almost completely transparent which may be exploited in flexible and transparent electrodes [5] for displays or solar cells. These are but a few possible applications of graphene. In order to bring graphene from the lab into the application, methods must be developed for a large scale production of graphene by epitaxial growth on a substrate. Epitaxial graphene on SiC(0001) [6] grows via thermal decomposition of the SiC substrate surface at elevated temperatures [7]. Because epitaxial graphene is atomically thin and recumbent on a substrate, it is an ideal subject for surface science tools. In my presentation I will demonstrate how various tools can be used to understand the properties of epitaxial graphene, to study and improve its growth, and to device methods for manipulating its interaction with the substrate. References [1] K. S. Novoselov, et al., Nature 438 (2005) 197; Y. Zhang, et al., Nature 438 (2005) 201. [2] V. V. Cheianov and V. I. Fal‘ko, Phys. Rev. B 74 (2006) 041403; M. I. Katsnelson, et al., Nature Physics 2,

(2006) 620. [3] J. S. Moon, et al., IEEE Electron Dev. Lett. 30 (2001) 650; Y.-M. Lin, et al., Science 327 (2010) 662; Y.

Wu, et al., Nano Lett. 12 (2012) 3062. [4] Y.-M. Lin, et al., Science 332 (2011) 1294. [5] X. Li, et al., Science 324 (2009) 1312; V. P. Verma, et al., Appl. Phys. Lett. 96 (2010) 203108; S. Bae, et

al., Nat. Nano. 5 (2010) 574. [6] C. Berger, et al., Science 312 (2006) 1191. [7] K. V. Emtsev et al., Nat. Mater. 8 (2009) 203. Contribution: Invited

 

25

Tuning the electronic properties of Silicene through half-hydrogenation or Graphene support

A. UGOLOTTI*,$, A. RAVIKUMAR$, G. FRATESI% and G.P. BRIVIO$ $ Dipartimento di Scienze dei Materiali, Università degli Studi di Milano-Bicocca, Italy % Dipartimento di Fisica, Università degli Studi di Milano, Italy * E-mail: a.ugolotti@campus.unimib.it Abstract: Silicene, the Si-based analogous of Graphene, has attracted much attention in the past years because of the new physics introduced by the Dirac structure(1) while suggesting an easy integration onto devices. However two main problems arise: how to grow it and how to tune its electronic properties to open a bandgap. Epitaxial techniques can lead to high control in the growth process, although only a small mismatch between the lattice of the supporting surface and that of the overlayer is allowed. Several supports have been successfully adopted(2) but one of the most common is Ag(111), for which the interaction regime has been proved to be strong enough to significantly change the properties of Silicene(3). In this direction part of our work is focused in addressing the role of support by considering a Silicene sheet deposited onto a graphene monolayer, two systems bound through van der Waals interactions and showing a good lattice match(4). It is found that even though the Dirac cones of the two layers are preserved upon adsorption, an interfacial charge transfer induces an energy shift of the states around the Fermi level that leads to a metallic interface(5). We employ ab initio spin-dependent density functional theory (DFT) and non-equilibrium Green’s function techniques to study and tune the electronic properties of such an interface in the presence of an external electric field. Another method to induce a bandgap in Silicene is, among the many techniques available(6), the covalent adsorption of an atomic species on the surface. In particular we consider H atoms, adsorbed at full coverage on both of the two sides of Silicene (namely Silicane) and on one side only (namely half-Silicane). We calculate the electronic and optical properties of these systems through DFT and Many-body Perturbation techniques, also considering the effect of adsorption on Ag(111). References: (1) Zhuang J et al., Sci. Bull., DOI: 10.1007/s11434-015-0880-2 (2) Zhao J et al., Prog. Mat. Sci. 83, 24, 2016 (3) Sheverdyaeva PM et al., ACS Nano 11, 975, 2017 (4) Nigam S et al., Phys.Chem.Chem.Phys. 17, 11324, 2015 (5) Shi L et al., J. Mater. Chem. A 4, 16377, 2016 (6) Rong W et al., Chin. Phys. B 24, 086807, 2015 Contribution: Oral

 

26

Elaboration and study of zinc and zinc oxide ultrathin layers on silver substrate at room temperature

H. MARADJ1,2, N. ROCHDI3, M. GHAMNIA2, C. FAUQUET1, B. EALET1, H. JAMGOTCHIAN1, J-P. BIBERIAN1, and B. AUFRAY1 1CINaM CNRS UMR 7325, Aix-Marseille Université, 13288 Marseille - France 2LSMC, Université d’Oran 1 Ahmed Benbella, 31100 Oran - Algeria 3SIAM, Faculty of Sciences Semlalia, Cadi Ayyad University, 4000 Marrakesh - Morocco E-mail : nabil.rochdi@uca.ma Abstract:

Auger Electron Spectroscopy (AES), Low Energy Electron Diffraction (LEED) and

Scanning Tunneling Microscopy (STM) were used to investigate the growth of ultrathin Zn and ZnO films on the Ag(110) surface at room temperature. Zinc oxide ultrathin layers were deposited on silver (110), at room temperature (RT) and in ultrahigh vacuum (UHV) conditions, using an appropriate Atomic Layer Deposition and Oxidation (ALDO) procedure [1] ; the latter consists sequentially in the RT deposition of a zinc monolayer, the exposure of the deposited monolayer to molecular oxygen, and the annealing of the sample in UHV conditions at medium temperatures. Such as for the deposition of other thin oxide layers [2,3], this procedure allows to synthetize a quite well ordered ZnO layer on the Ag(110) surface in the early growth stages. Based on the STM characterization performed after the oxide growth, we propose a schematic atomic model which reveals a lateral expansion of 1.5% of the ZnO unit cell in good agreement with Surface X-Ray Diffraction results of ZnO thin film deposited on Ag(111) [4]. At Zn coverage close to one monolayer, a new c(14×6) superstructure is observed by LEED and a Moiré pattern due to a weak rotation of a pure dense plane of Zn is revealed by STM study of the surface: A schematic ball model of the Zn monolayer on Ag(110) is proposed. References: [1] S. Vizzini, H. Oughaddou, J. Y. Hoarau, J. P. Bibérian, and B. Aufray, “Growth of ultrathin film aluminum oxide on Ag(111)”, Appl. Phys. Lett. 95(17), 173111 (2009). [2] N. Rochdi, K. Liudvikouskaya, M. Descoins, M. Raïssi, C. Coudreau, J.-L. Lazzari, H. Oughaddou, and F. Arnaud-d’Avitaya “Surface morphology and structure of ultra-thin magnesium oxide grown on (100) silicon by atomic layer deposition oxidation” Thin Solid Films 519, 6302 (2011). [3] N. Rochdi, M. Raïssi, S. Vizzini, C. Coudreau, J.-L. Lazzari, B. Aufray, H. Oughaddou, and F. Arnaud-d’Avitaya, “Structural and electrical characterizations of nanometer scaled aluminum oxide in metal / insulator / silicon (100) heterostructures”, G. J. Phys. Chem. 2(2), 230 (2011). [4] C. Tusche, H. Meyerheim, and J. Kirschner, “Observation of Depolarized ZnO(0001) Monolayers: Formation of Unreconstructed Planar Sheets”, Phys. Rev. Lett. 99(2), 26102 (2007). Contribution: Oral

 

27

Spectroscopy and Synthesis of Bismuthene

L. Dudy,1,4, F. Reis1, G. Li2,3, M. Bauernfeind1, S. Glass1, W. Hanke3, R. Thomale3, J. Schäfer1, and R. Claessen1

1 Physikalisches Institut and Röntgen Center for Complex Material Systems, Universität Würzburg, Germany

2 School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China. 3 Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Germany

4 Synchrotron Soleil, L'Orme des Merisiers, 91190 Saint-Aubin, France The hunt for quantum-spin-Hall materials with large band gap is one of most vivid fields of contemporary solid state physics. In all systems reported so far, the bottleneck, preventing the use of the dissipationless currents with spin-momentum locking inherent in those materials for device applications, was their small energy gap, requiring very low operation temperatures. Despite other approaches, Graphene with its honeycomb lattice geometry always fascinated the research community. In order to enlarge the bandgap, several theoretical proposals for heavy atom honeycomb lattices, e.g. Silicene, Germanene, Stanene, have been made and attracted great attention. We present the realization of a honeycomb lattice of a high-Z element, namely bismuth, which is synthesized on the wide-bandgap substrate SiC(0001). Scanning tunneling microscopy imaging of Bismuthene clearly displays the honeycomb structure, both in the occupied and unoccupied states of the sample. Using tunneling spectroscopy, we find a huge bulk gap of around 800 meV, with the Fermi level positioned well inside this gap. A comparison of angle-resolved photoemission measurements and density functional theory band structure calculations is further manifesting the formation of Bismuthene. Interestingly, metallic edge states are observed when the edge of the Bi film is approached. Both findings are consistent with theoretical expectations. In order to understand the empirical electronic properties, a detailed theoretical analysis was performed. A low-energy effective model demonstrates that the substrate not only stabilizes the Bi film, but plays a crucial role in the formation of the observed band gap, which is driven by the large on-site spin-orbit coupling. F. Reis et al., Science 357, 287 (2017) Contribution Invited

 

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In-situ STM measurements of Si growth on layered materials A. CURCELLA, Y. BORENSZTEIN, R. BERNARD and G. PREVOT Sorbonne Universités, UPMC Univ Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris, F-75005, Paris, France E-mail : curcella@insp.upmc.fr

Abstract: In the last few years the synthesis of silicene layers has been reported on several metallic substrates, such as Ag(111), Ir(111), ZrB2(0001). Unfortunately, the strong interaction with the substrate deeply affects the bidimensional silicon layers and their electronic properties, which are utterly different from those expected for free-standing silicene. Several ways have been attempted in order to obtain a decoupled silicene layer: passivation of the substrate, synthesis of multi-layer silicene and Si deposition on layered materials1,2. We performed Si evaporation on four van der Waals layered materials in UHV conditions: HOPG (semimetal), MoS2 (semiconductor), TiTe2 (semimetal) and ZrSe2 (semiconductor). For all these materials, in the 273 K-476 K temperature range we have observed the nucleation and growth of 3D islands using real-time STM. This technique allows to follow the evolution of the substrate during Si evaporation, so to tell apart the effect of the deposited Si and the defects or reconstructions of the substrate surface. On HOPG, Si islands induce a 3× 3  𝑅30° reconstruction in their surroundings, which has been interpreted in terms of

charge density modulation, an effect already reported in the case of metal clusters on graphite. References: 1Chiappe, D. et al., Adv. Mater. 2014, 26, 2096. 2De Crescenzi, M. et al., ACS Nano 2016, DOI: 10.1021/acsnano.6b06198. Contribution: Oral

2 nm

Figure 1: Room temperature STM observation of HOPG after deposition of about 0.2 monolayer of Si (U=0.20 V, I=50 pA). In the left part we see the √3×√3  𝑅30° reconstruction gradually changing to the unreconstructed graphite surface, on the right part.

Si island

 

29

Epitaxial growth of silicene on passivated Si:B substrates : Preliminary studies

H. MREZGUIA1, 2, A.AKREMI1, Y.KSARI2, L.GIOVANELLI2, J.-M.THEMLIN2

1Spectromètre de Surfaces, LR01ES15, Faculty of Sciences of Bizerte, University of Carthage, 7021 Jarzouna, Bizerte, Tunisie 2 IM2NP UMR 7334, Aix Marseille Univ, University Toulon, CNRS, Marseille 13397, France E-mail : hela.mrezguia@im2np.fr Abstract:

To circumvent the physical limitations of graphene, suitable two-dimensional materials, especially with a sizeable bandgap, are needed to extend the range of applications in micro/nano-electronics. In this respect, silicene is a promising material which has been deposited on several substrateslike silver[1], ZrB2[2], iridium[3]... The present work is devoted to the heteroepitaxial growth of two-dimensional nanomaterials like silicene or germaneneon silicon substratespassivated by boron.

In the first part, we present the results of the preparation of the B-doped substrate Si(111)-(√3×√3)R30°: B (in short Si:B)under ultra-high vacuum.The structural, chemical and electronic properties of thispassivated surface have been investigated using low-energy electron diffraction (LEED), Auger electron spectroscopy (AES), X-ray and ultraviolet photoemission spectroscopies (XPS, UPS) and inverse photoemission spectroscopy (ARIPES), a technique which provides access to the unoccupied electronic statesnear the Fermi level. While the usual (√3𝑥√3) R30° reconstruction is obtained for the clean Si(111):B surface, the IPES spectrum obtained after annealing at 950°C for 10 min exhibits four peaks at normal incidence. While the lower one is assigned to a surface state, two other peaks are assigned to volume states of the Si substrate, and a fourth to a default. The experimental dispersion of the surface state revealed by ARIPES shows that the peak moves towards the Fermi energy away from the Brillouin zone center, in accordance with the literature[4].

Finally, we present the first trials of Si evaporationon Si:B substrates, studiedby LEED, AES and ARIPES. We show that the evaporationrate and the substrate temperature are important parameters to control the formation ofsilicene on Si:B. References: [1] P. Vogt, P . Padova, C. Quaresima, J. Avila, E. Frantzeskakis, M. Carmen Asensio, A. Resta, B. Ealet, and G. Le Lay, Physical Review Letters108 (2012) 155501 [2] A. Fleurence, R. Friedlein, T. Ozaki, H. Kawai, Y. Wang, and Y. Yamada-Takamura, Physical Review Letters108, (2012) 245501 [3] L. Meng, Y. Wang, L. Zhang, S. Du, R. Wu, L. Li, Y. Zhang, G. Li, H. Zhou,W. A. Hofer and H. Gao. Nano Lett. 13 (2013) 685 [4].E.Kaxiras,K.C.Pandy, F.J.Himpsel, and R.M.Tromp, Phys.Rev.B41 (1990)1262 Contribution: Poster

 

30

FITIR spectroscopy and Optical transmission study of nanocrystalline Silicon Carbide thin films.

K. KEFIF, LPCMME, Faculté des Sciences Exactes et Appliquées, Université d’Oran 1, Ahmed Ben Bella, BP 1524, El M’naouar, 31000 Oran, Algeria. E-mail : kefifk@gmail.com Abstract: The present study reports on a detailed investigation on the transition from amorphous to nanocrystalline silicon carbide films grown by means of reactive radiofrequency magnetron sputtering process at low substrate temperatures Ts ranging from 200 ◦C to 500 ◦C. Fourier transform infrared spectroscopy (FTIR), optical transmission measurements and atomic force microscopy (AFM) images were used to study the structural and the optical properties of the films. The results clearly show that hydrogen atoms play a crucial role in the nanocrystal nucleation mechanism. The grown of the films is governed by the interactions between hydrogen atoms and SiC amorphous matrix. The FTIR analysis showed an abrupt structural transition from amorphous a-SiC:H to nc-SiC:H films occurred with increasing Ts from 250 ◦C to 300 ◦C. Upon increasing Ts, the extent of crystallization is substantial and reaches (70 ± 2) % for films deposited at 500 ◦C. In parallel, the total bonded hydrogen content decreases from 30 at.% to less than 6 at.%. The AFM observations confirm the structural changes in the films, and the average grain size reaches a value of about 60 nm. Bouizem  Y,  Kefif  K  (Journal of Non-Crystalline Solids)2012, Kefif K, Bouizem Y (Optik) 2017. Contribution: Poster

 

31

Epitaxial Sn on h-BN terminated ZrB2 MICHAL OCHAPSKI, FRANK WIGGERS, MICHEL DE JONG MESA+ Institute, NanoElectronics Group, University of Twente E-mail : m.w.ochapski@utwente.nl Abstract: Stanene, the tin analogue of graphene, is a 2-dimensional (2D) Dirac material that promises a wealth of physical phenomena [1-6] and bright perspectives for electronic applications. Free-standing stanene is predicted to feature Dirac fermions near the Fermi energy just like its carbon counterpart. Spin-orbit coupling may be much larger than in graphene, silicone or germanene, such that it could support a large-gap 2D quantum spin Hall (QSH) state, and thus enable the dissipationless electric conduction at room temperature[1-3]. It could also provide enhanced thermoelectricity [4], topological superconductivity [5], and the near-room-temperature quantum anomalous Hall (QAH) effect [6]. In spite of these promising properties predicted theoretically, the synthesis of (free-standing) stanene still remains a major challenge. So far there is only one report of epitaxialy grown stanene [7]. The electronic structure differs considerably from the theoretically predicted electronic properties of free standing stanene, because of the interaction with the substrate. Moreover, further discrepancies between the experimentally observed band structure and theory were attributed by the authors to unintentional hydrogenation of the stanene. The chemical sensitivity of stanene forms a complexity in its synthesis, but could also allow for engineering of its electronic properties. Recently, we found that, after Sn deposition on silicene- and h-BN terminated ZrB2(1111) epitaxial thin films on Si(111) wafers, we could observe various new surface reconstructions, attributed to Sn, in LEED pictures of both samples. Preliminary APRES measurements show new metallic bands, however due to the heterogeneous character of the surface (observed by PES and LEED) after Sn deposition, these could only be observed on a small part of the sample. Various different ordered Sn-phases are to be expected, based on previous PES and LEED results, with presumably different band structure. Exploration of these Sn layers could contribute strongly to stanene research. References: [1] Xu.et al. PRL 111,136804 (2013). [2] Liu et al. PRB 84, 195430 (2011). [3] Zhang et al. PRB 90, 075114 (2014). [4] Xu et al. PRL 112, 226801 (2014). [5] Wang et al. PRB 90, 054503 (2014). [6] Wu et al PRL 113, 256401 (2014). [7] Zhu F et al. Nat. Mater. 14 1020 (2015) Contribution: Poster

 

32

Hamilton-Jacobi Method of Gauge Invariant Systems

Dr. Khaled Nawafleh Department of Physics, Mutah University, Jordan E-mail : knawaflehh@yahoo.com Abstract: This study seeks to investigate equations of motion for gauge symmetry Lagrangians as well as to make quantization using the WKB approximation. To this end, the techniques of separation of variables and the method of canonical transformations to solve the Hamilton-Jacobi equation were applied. References: Arnold,V. (1989). Mathematical Methods of Classical Mechanics, 2nd edition, Springer-Verlag, Berlin.

Althubyani, H.(2012). Hamilton-Jacobi Analysis of Reparametrized Lagrangian Systems and path integral

quantization. Unpublished MA thesis, Mu'tah University.

Ashraf, A. (2010). Quantum Time: Time as a Dynamical Variable. Franklin and Marshall College Physics and

Astronomy. Unpublished MA thesis

Baleanu, D. (2004). Reparametrization invariance and Hamilton-Jacobi formalism, Institute of Space Sciences,4,

2-3.

Baleanu, D., & Güler, Y.(2003). Chain and Hamilton - Jacobi approaches for systems with purely second class

constraints, Nuovo Cimento, 6, 615.

Dirac ,M. (1967). Lectures on Quantum Mechanics. Yeshiva Univ. Press, New York.

Goldstein, H.(1980).Classical Mechanics, 2nd edition, Addison-Wesley. New York.USA.

Goldstein,H.(2000). Classical Mechanics, 3rd edition, Addison-Wesley. New York.USA.

Griffiths,D.(1999). Introduction to electrodynamics, 3rd ed. (Prentice, N.J., 1999).

Contribution: Poster

 

33

Interface sensitive structure determination of silicon nano-ribbons on Au(110) using photoelectron diffraction (XPD)

Peter Roese(a,b), Philipp Espeter(a,b), Karim Shamout(a,b), Ulf Berges(a,b), Carsten Westphal(a,b) (a) Experimentelle Physik 1, Technsiche Universität Dortmund, Germany (b) DELTA, Technsiche Universität Dortmund, Germany Corresponding author: Peter Roese, E-mail : peter.roese@tu-dortmund.de Abstract: In the last years there has been much progress in the growth and analysis of 2D-materials beyond graphene on metallic surfaces. Especially, silicon based two-dimensional silicene [1] and one-dimensional silicon nano-ribbons [2] came into scientific focus due to their promising electronic properties [3, 4]. Beside the exact knowledge of the fascinating electronic and chemical properties of such systems, the structural information is of great interest for precise DFT calculations [6, 7]. For the fabrication of electronic devices nano-ribbons will be removed from the conducting surface and they are transferred onto an insulator. In this context the interaction between the silicon nano-ribbons and the substrate plays an important role. Techniques like STM or LEED provide information about the electronic structure of such systems but neither chemical information about the atomic bonds nor information about the interface. Photoelectron spectroscopy and diffraction easily provide information about atomic bonds and the interface between silicon nano-ribbons and the substrate, recently shown by Espeter et al [8]. Previous publications showed the preparation of silicon nano-ribbons with a width of about 1.6 nm on Ag(110) [2, 9, 10] as well as on Au(110) [11]. The structure of silicon nano-ribbons on Ag(110) has recently been resolved [3, 8, 12] whereas their exact structure on Au(110) and the effect of the interface needs to be analyzed in detail. Based on previous works, we present first photoelectron diffraction results of silicon nano-ribbons on Au(110). [1] Vogt et al., Phys. Rev. Lett. 108, 155501 (2012) [2] Leandri et al., Surf. Sci. 574, L9 (2005) [3] Cerdá et al., Nat. Commun. 7, 13076 (2016) [4] Padova et al., J. Phys. Condens. Matter 25, 014009 (2012) [6] Kara et al., J. Phys.: Condens. Matter 22, 045004 (2010) [7] He et al., Phys. Rev. B 73, 035311 (2006) [8] Espeter et al., Nanotechnology 28, 455701 (2017) [9] Feng et al., Surf. Sci. 645, 74 (2016) [10] Aufray et al., Apll. Phys. Lett. 96, 183102 (2010) [11] Tchalala et al., Appl. Phys. Lett. 102, 083107 (2013) [12] Prévot et al., Phys. Rev. Lett. 117, 276102 (2016) Contribution: Poster

 

34

Silicene Growth On NaCl Thin Films Khalid Quertite1,3,4, Karima Lasri2, Hanna Enriquez1, Andrew J. Mayne1, Abdelkader Kara2, Azzedine Bendounan3, Pierre Lagarde3, Gérald Dujardin1, and Nicolas Trcera3, Abdallah El kenz4, Abdelilah Benyoussef4,5 and Hamid Oughaddou1,6

1Institut des Sciences Moléculaires d’Orsay, ISMO-CNRS, Bât. 210, Université Paris-Sud, 91405 Orsay, France 2Department of Physics, University of Central Florida, Orlando, FL 32816, USA 3Synchrotron Soleil, L’Orme des Merisiers Saint-Aubin, B.P. 48, 91192 Gif-sur-Yvette Cedex, France 4LMPHE, Faculté des Sciences, Université Mohammed V - Agdal, Rabat, Morocco 5Institute of Nanomaterials and Nanotechnology, MAScIR, Rabat, Morocco 6Département de Physique, Université de Cergy-Pontoise, 95031 Cergy-Pontoise Cedex, France Abstract : Silicene the silicon based analog of graphene has a 2D structure that could have some attractive electronic properties: massless Dirac fermions, high electron mobility… It is a particularly promising material for nanotechnology because it can be integrated into industry-based silicon electronics. The existence of silicene has been achieved recently by epitaxial growth of silicon on the noble metal substrate Ag and Au. However, the electronic interaction between silicene and the metallic substrates is strong and could mask its electronic properties. In order to access the intrinsic properties of silicene we plan to grow silicene on an insulating material such as NaCl. We have grown thin film of NaCl (1 ML) on Ag(110) surface. The STM images show that NaCl film presents a large and defect free area and presents a (4x1) superstructure. The Theoretical calculations (DFT) of NaCl on Ag(110) substrate support the experimental observations already found. Deposition of silicon atoms on NaCl induces a (4x3) superstructure and the STM images show that silicon forms a silicene sheet with a honeycomb like structure. In order to get access to the silicene electronic structure, experiments using Synchrotron facilities at SOLEIL such as EXAFS and ARPES techniques are programmed in LUCIA and TEMPO beam-lines. Contribution: Poster

 

35

Experimental and theoretical optical investigation

of silicene and Si layers on Ag Yves Borensztein1, Alberto Curcella1, Geoffroy Prevot1, Conor Hogan2,3, Olivia Pulci3, Paola Gori4, Friedhelm Bechstedt5, David Martin6

1 Institut des NanoSciences de Paris, Sorbonne Université et CNRS, 75005 Paris, France 2 Istituto di Struttura della Materia-CNR (ISM-CNR), Rome, Italy 3 Dipartimento di Fisica, Universita di Roma “Tor Vergata”, Rome, Italy 4 Dipartimento di Ingegneria, Universit´a di Roma Tre, Rome, Italy 5 IFTO, Friedrich Schiller Universit¨at, Max-Wien Platz 1, Jena 6 Department of Physics, University of Liverpool L69 7ZE, UK

Abstract: We present a combined experimental and theoretical study of the optical properties of silicene and of single-layer Si 1D and 2D nanostructures supported on Ag(111) and Ag(110) substrates1,2. Ab initio calculations of the reflectance anisotropy spectra (RAS) and surface differential reflectivity spectra (SDRS) for the clean Ag surface and for the Ag/Si interfaces are compared with experimental measurements. The absorption spectrum of a silicene sheet computed including excitonic and local field effects is found to be quite similar to that calculated within an independent particle approximation, at least within the optical range. For Ag(110)/Si we confirm the presence of a pentagonal nanoribbon structure, strongly bonded to the substrate, and rule out competing zigzag chain models. The origins of the RAS and SDRS signals are explained. For Ag(111)/Si we reproduce the main experimental features and extract a signal of the epitaxial silicene overlayer. Important details of the computational approach are examined. Our results therefore do not find evidence for Si adlayers that retain the properties of the free standing silicene. References: (1) Borensztein, Y.; Prévot, G.; Masson, L. Large Differences in the Optical Properties of a Single Layer of Si on Ag(110) Compared to Silicene. Phys. Rev. B 2014, 89. (2) Matthes, L.; Pulci, O.; Bechstedt, F. Optical Properties of Two-Dimensional Honeycomb Crystals Graphene, Silicene, Germanene, and Tinene from First Principles. New J. Phys. 2014, 16, 105007. Contribution: Poster

2

 

36

List  of  participants    

First name Last name Affiliation Country E-mail

Mustapha AIT ALI Cadi Ayyad University Morocco Aitali@uca.ac.ma Curcella ALBERTO UPMC - INSP France Alberto.curcella@gmail.com

Maria C. ASENSIO Synchrotron SOLEIL France Asensio@synchrotron-soleil.fr

Bernard AUFRAY CINaM-CNRS Marseille France Aufray@cinam.univ-mrs.fr

Jose AVILA Synchrotron SOLEIL France Avila@synchrotron-soleil.fr

Salvador BARRAZA-LOPEZ

Department of Physics. University of Arkansas

United States of America

Sbarraza@uark.edu

Azzedine BENDOUNAN Synchrotron SOLEIL France Azzedine.bendounan@synchrotron-soleil.fr

Abdelilah BENYOUSSEF MASCIR Morocco Benyous.a@gmail.com

Yves BORENSZTEIN Inst des Nanosciences de Paris - UPMC - CNRS France Yves.borensztein@insp.jussieu.fr

Lenart DUDY Synchrotron Soleil France Lenart.dudy@synchrotron-soleil.fr

Gerald DUJARDIN Institut des Sciences Moleculaires dOrsay (ISMO)

France Gerald.dujardin@u-psud.fr

Hanna ENRIQUEZ ISMO, Université Paris-Sud France Hanna.enriquez@u-psud.fr

Guido FRATESI Physics Department, University of Milan Italy

Guido.fratesi@unimi.it

Brivio GIANPAOLO University of Milano-Bicocca Italy Gianpaolo.brivio@unimib.it

Ming HU RWTH Aachen University Germany Hum@ghi.rwth-aachen.de

Haik JAMGOTCHIAN Aix-Marseille Université, CNRS, CINaM, UMR 7325

France Jamgotchian@cinam.univ-mrs.fr

Abdelkader KARA University of Central Florida

United States of America

Abdelkader.kara@ucf.edu

Kefif KHEIRA LPCMME, ORAN1 UNIVERSITY Algeria Kefifk@gmail.com

Pierre LAGARDE Synchrotron Soleil France Pierre.lagarde@synchrotron-soleil.fr

Karima LASRI University of Central Florida

United States of America

Karima.lasri@ucf.edu

Jean Louis LEMAIRE Universite Paris Sud France Jean-louis.lemaire@u-psud.fr

Laurence MASSON CINaM, Aix-Marseille Université France Masson@cinam.univ-mrs.fr

Andrew MAYNE ISMO-CNRS France Andrew.mayne@u-psud.fr

Paolo MORAS Istituto di Struttura della Materia - CNR Italy Paolo.moras@ism.cnr.it

 

37

Omar MOUNKACHI Materials and Nanomaterials Center, MAScIR

Morocco O.mounkachi@mascir.com

Hela MREZGUIA IM2NP (Aix Marseille University) France Hela.mrezguia@im2np.fr

Khaled NAWAFLEH Mutah University Jordan Knawaflehh@yahoo.com

Michal OCHAPSKI University of Twente Netherlands M.w.ochapski@utwente.nl

Hamid OUGHADDOU ISMO-CNRS, Université de Cergy-Pontoise France Hamid.oughaddou@u-psud.fr

Geoffroy PReVOT Institut des NanoSciences de Paris France Prevot@insp.jussieu.fr

Khalid QUERTITE ISMO-CNRS France Khalid.quertite@u-psud.fr

Viktoria RITTER University of Technology Vienna Austria Viktoria.ritter@tuwien.ac.at

Nabil ROCHDI SIAM-FSSM, Cadi Ayyad University Morocco Nabil.rochdi@uca.ma

Peter ROESE Technische Universität Dortmund Germany Peter.roese@tu-dortmund.de

Fabio RONCI Istituto di Struttura della Materia-CNR (ISM-CNR) Italy Ronci@ism.cnr.it

Thomas SEYLLER TU Chemnitz Germany Thomas.seyller@physik.tu-chemnitz.de

Mathieu SILLY synchrotron Soleil France Mathieu.silly@synchrotron-soleil.fr Nori TAKAGI The Universtiy of Tokyo Japan N-takagi@k.u-tokyo.ac.jp

Laurene TETARD University of Central Florida

United States of America

Laurene.tetard@ucf.edu

Yongfeng TONG synchrotron soleil France Tongyf11@gmail.com

Aldo UGOLOTTI Universita degli Studi di Milano-Bicocca Italy A.ugolotti@campus.unimib.it

Holger VACH CNRS - LPICM, Ecole Polytechnique France Holger.vach@polytechnique.edu

Wei ZHANG ISMO-CNRS France Wei.zhang1@u-psud.fr

 

38

Notes    

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Notes    

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Notes    

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