Superconductor Spintronics - phy.pku.edu.cn

© 2014 ICQM

Chapter 9

Superconductor Spintronics

韩伟

量子材料科学中心

2019年12月09日

2

Review of last class

1. Antiferromagnetism and Exchange bias

2. Spin Seebeck effect in AFM

5. Anomalous Hall effect in AFM

3. AMR of AFM

6. Spin Hall effect in AFM

4. Switching of AFM

7. Spin current flow in AFM

3


Rezende, et al, PRB, 93, 014425 (2016)

Spin Seebeck effect in AFM

4


AFM memory

Wadley et al, science 351, 587(2016)

5


AHE and SHE in AFM

6


Spin current flow in AFM

7

Outline

1. Coupling between FM and SC

3. Spin Triplet pairs

4. Spin superconductor

5. Spin/magnon—SC cavity coupling

2. FM Josephson junctions

8

Outline


9

Competing between FM and SC

Superconductor:

Ferromagnetism (anti):

10

Proximity effect vs. Andreev reflection

Proximity effect Andreev reflection

Coupling between FM and SC

11

S/N vs S/F

A.I.Buzdin, Rev. Mod. Phys 77(3) 935-977 (2005)

��

Superconductor proximity effect

12

Andreev Reflection

13

Superconductor proximity effect

G. Miao, et al, Phys.Rev.Lett.101.137001(2008)

V (S)/ Fe (FM) tunneling junction

14

N/S F/S

C. Visani, et al, Nat. Phys. 10.1038 (2012)

Andreev Reflection

15C. Visani, et al, Nat. Phys. 10.1038 (2012)

YBa2Cu3O7 /La0.7Ca0.3MnO3SC/ half-metal:

Spin-triplet Andreev Reflection

16C. Visani, et al, Nat. Phys. 10.1038 (2012)

YBa2Cu3O7 /La0.7Ca0.3MnO3

@ T= 3K

SC/ half-metal:


17


C. Visani, et al, Nat. Phys. 10.1038 (2012)

McMillan-Rowell resonance

18

Superconductor spintronics

Quasiparticles

Spin-triplet

19

Superconductor spintronics

Long spin lifetime Large Spin Hall effect

Yang, et al, Nature Materials, 9 , 586–593 (2010)Wakamura, et al, Nature Materials, 14 , 675–678 (2015)

20

Outline


21

Josephson junction

Single electron tunneling? Tunneling as a pair?

VS

22

What is a � junction?

Lecture from Prof. Brige

N/F

23

� Josephson junction in S/N/S system

Baselmans, et al, Nature 397, 43 (1999)

24

� Josephson junction in S/I/F/S system

T. Kontos, et al, Phys. Rev. Lett. 86, 304 (2001)

25

� Josephson junction in weak FM

T. Kontos, et al, Phys. Rev. Lett. 89, 137007 (2002)

Q(E): Spectral current density

26

� Josephson junction in weak FM

Nb /Cu0.47Ni0.53 /Nb

V.A. Oboznov, et al, PRL 96, 197003 (2006)

27

� Josephson junction in strong FMI c

RN(m

V)

dF(nm)

Robinson, Blamire, et al, PRL 97, 177003 (2006)

Nb /Co /Nb

Nb /Py /Nb

28

Quantum Qubit applications

29

Outline


30

S = 1

S = 0

Spin Triplet pairs

Spin-singlet

Spin-triplet

31J. Linder & W. A. Robinson, Nature Phys. 11, 307–315 (2015)

Spin-triplet supercurrent

32


33

S F

Bergeret, Volkov & Efetov, PRL 90, 117006 (2003)


Long-range transport of spin-triplet in FM

34

Spin-triple supercurrent

Kerizer, et al, Nature 439, 825 (2006)

0.3 -1 um

Half-Metallic Josephson junction

35




36




37Teun Klapwijk, Nature Physics 6, 329 (2010)

Spin singlet to triplet conversion


38

Spin triplet Josephson junction

X = Co

X = PdNi (4nm)

Cooper pairs feel noncollinear M between X and Co layers

Khaire, Khasawneh, Pratt, & Birge, Phys. Rev. Lett. 104, 137002 (2010)


39


W.A. Robinson, et al, Science 329 (5987), 59-61 (2010)


40W.A. Robinson, et al, Science 329 (5987), 59-61 (2010)



41Eschrig, Physics Today, 64, 43 (2011)



42

Spin pumping into Superconductor

K.R. Jeon, et al, Nat. Mater. 17, 499–503(2018)

Non-equilibrium spin-triplet supercurrent

43




44




45K.R. Jeon, et al, Nat. Mater. 17, 499–503(2018)


46

休息10分钟

47

48

Outline


49

Spin superfluidity:

Spin superfluidity:

Spin analogue of superconductivity

50

Charge superconductivity: Zero resistance

Spin superfluidity:Zero spin resistance

Sp

in S

ign

al

T (K)

Q. Sun and X. C. Xie, PRB 84, 214501 (2011), PRB 86, 085441 (2012), Nature Comm. 4, 2951(2013)

Spin superfluidity

Spin superfluidity: Spin analogue of superconductivity

51

Charge superconductivity: Meissner effect (B)

Spin superfluidity:Meissner effect (E)

Q. Sun and X. C. Xie, PRB 84, 214501 (2011), PRB 86, 085441 (2012)


Spin superfluidity

52

Charge superconductivity: Josephson effect

Spin superfluidity:Spin-Josephson effect

Sun and Xie, PRB 84, 214501(2011), PRB 86, 085441(2012)Liu, et al, PRB (2014)Chen, Kent, MacDonald, PRB 90, 220401(R) (2014).

Spin superfluidity


53

Charge superconductivity: Spin superfluidity:

ie, Wang, et al, Science (2011)

e-h BECCharge: 0Spin pairs: (1/2 + 1/2)

Magnon BECCharge: 0Magnon: Spin-1

Sonin, JETP 74,2079-2111(1978)Q. Sun and X. C. Xie, PRB (2011), PRB (2012), Nature Comm. (2014)S.Takei, et al, PRB 90, 094408 (2014)


Spin superfluidity

54

Spin superfluidity

55

Spin Superfluidity Materials

1) He-3

Spin-polarized

Book：Superfluidity and superconductivity (David R. Tilley, John Tilley)

S = 1⁄2

56


Borovik-Romanov, et al, JETP Lett. 45, 124 (1987)Review: Sonin, Advances in Physics (2010)

Spin polarized He3 Superfluid spin “Current”

1) He-3

57


1) He-3

A. S. Borovik-Romanov, et al, JETP Lett. 45, 124 (1987)

Phase slippage

58


Borovik-Romanov, et al, JETP Lett. 45, 124 (1987)Review: Sonin, Advances in Physics (2010)

Solid State Materials?

Spin polarized He3 Superfluid spin “Current”

1) He-3

59


2）Magnon in Ferromagnetic materials

FM

Magnon (Charge 0, Spin-1 boson)

60


2）Magnon BEC

Magnon BEC by parametric pumping

S. O. Demokritov, et al, Nature 443, 430 (2006)D. A. Bozhko, et al, Nat. Phys. 12, 1057 (2016)

61


2）Magnon BEC

S. O. Demokritov, et al, Nature 443, 430 (2006)D. A. Bozhko, et al, Nat. Phys. 12, 1057 (2016)

Magnons flow between two Magnon BECs Spin superfluidity (< ~ 1 Micro second)

62


3) Spin superfluidity in AFM (FM graphene)

e-h BECCharge: 0Spin pairs: (1/2 + 1/2)

Q. Sun and X. C. Xie, PRB 87, 245427 (2013)Takei, et al, PRL 116, 216801(2016)Q. Sun and X. C. Xie, PRB 84, 214501(2011)

v = 0 quantum state of graphene

Novoselov et al., Nature 438, 197–200 (2005)Zhang et al., Nature 438, 201–204 (2005)

Proximity-induce FM graphene

63


3) Spin superfluidity in canted AFM (insulator)

Magnon Charge: 0Magnon: Spin-1 boson

Takei, et al, PRB 90, 094408 (2014)

64


AFM Phase in v = 0 graphene

A.F. Young, et al, Nature 505, 528–532 (2014)

65


Spin current as a probe of spin superfluidity

Takei, et al, PRB 90, 094408 (2014)Takei, et al, PRL 115, 156604 (2015)

66

[0001]

O

Cr

Cr2O3 AFM insulator

Al2O3

Cr2O3

500 nm

1 nm

-1 nm

1 nm

-1 nm

500 nm

Atomic flat (0001)-Cr2O3 AFM films

~ 19 nm

(0001)-oriented Cr2O3

Pulsed Laser deposition

Spin Superfluidity in canted AFM

67

Pt Pt

Cr2O3

x

y

z

B

S1

S2

mx

Nonlocal spin transport

Field induced Canted AFM

0 60 120 180 240 300 360

-0.4

-0.2

0.0

0.2

0.4 R

2

sin ()

R2w

(V/A

2)

φ (degree)

d = 10 µm

Js Mφ

B

.VNL

..I

Thermal spin injection

Spin current detector (ISHE)

RNL detects spin conductance

Nonlocal technique previously developed to study Magnon diffusion in ferromagnetic insulator YIG:Cornelissen, et al, Nat. Phys. 11,1022–1026(2015)


68

Saturation of the nonlocal spin signal

Saturation of the nonlocal spin signal (spin conductance )

Spin superfluidity in canted AFM


69

Slow decay:

Lα related to the damping of AFM

Takei, et al, PRB 90, 094408 (2014)Sonin, Private communications (2018)

��~��

� + ��

Long distance spin transport


70

Fast decay (magnon diffusion): Slow decay:

Lα related to the damping of AFM

Takei, et al, PRB 90, 094408(2014)

Similar to incoherent magnons in YIG:Cornelissen, et al, Nat. Phys.11,1022–1026 (2015)

��~exp(� �⁄ )

1 − exp(2 � �⁄ )

��~��

� + ��

Comparison with incoherent magnons


71

Critical current density

A critical spin current (IS) density is needs to overcome AFM pinning (anisotropy)


Pt Pt

Cr2O3

x

y

z

0.0 2.5x10-7 5.0x10-7

0

10n

20n

30n

40n

50n

V2w

NL (

V)

I2inject (A2)

T=2K T=5K

72

Saturation of the nonlocal spin signal at LT

Long distance spin transport (length dependence)

Critical current for spin superfluidity

Phase diagram of field-induced canting

Pt Pt

Cr2O3

W. Yuan, Q. Zhu, T. Su, Y. Yao, W. Xing, Y. Chen, Y. Ma, X. Lin, J. Shi*, R.Shindou, X. C. Xie*, and Wei Han*, Science Advances, 4: eaat1098 (2018)


73

Question: Does spin superfluidity exist in all canted AFM?


74

Question: Does spin superfluidity exist in all canted AFM?


No

75


Fe2O3

Incoherent magnon Lebrun and Klaui, et al, Nature 561, 222–225 (2018)

76


(11-20) oriented Fe2O3 on Al2O3

32 34 36 38 40 42

Al2O3 (11-20)

Inte

nsity

2Theta (Degree)

Fe2O3 (11-20)

0 50 100 150 200 250

0.00

0.04

0.08

0.12

0.16

R

NL

(V/A

2)

T (K)

Incoherent magnon

Fe2O3

77


Fe2O3

1 2 3 4 5

0.1RN

L(V

/A2)

L (mm)

��~exp(� �⁄ )

1 − exp(2 � �⁄ )

W. Xing, Y. Ma, et al, unpublished

T = 150 K

0.0 5.0x10-7

1.0x10-6

0.00

0.05

0.10

IAC2 (A2)

V2w

(mV

)

T = 150 K

78


W. Xing, L. Qiu, X. Wang, Y. Yao, Y. Ma, R. Cai, S. Jia, X. C. Xie, and Wei Han*, Physical Review X 9, 011026 (2019)

10 μm

10 μm

0 2 4 6 8 10 12 14 16

0.1

1

��~exp(� �⁄ )

1 − exp(2 � �⁄ )

��~exp(� �⁄ )

1 − exp(2 � �⁄ )

13 nm

24 nm

0 2 4 6 8 10 120.01

0.1

1

10

79Takei, et al, PRL 115, 156604 (2015)Petr Stepanov, et al, Nature Physics 14, 907–911(2018)

Spin Superfluidity in quantum AFM

Quantum AFM Phase in v = 0 graphene

80Petr Stepanov, et al, Nature Physics 14, 907–911(2018)



81Petr Stepanov, et al, Nature Physics 14, 907–911(2018)

Saturation of nonlocal signal



82

Spin superfluidity

Magnon BEC(< 1 μs)

Solid State Materials

Pt Pt

Cr2O3

Canted AFM Cr2O3

Graphene (ν = 0)

Spin Superfluidity

83

Spin superfluidity

Magnon BEC(< 1 μs)

Solid State Materials

Pt Pt

Cr2O3

Canted AFM Cr2O3

Graphene (ν = 0)

Spin Superfluidity

The Rise of Spin Superfluidity!

84

Outline


85

Cavity spintronics

Image from Prof. Can-Ming Hu

86Dany Lachance-Quirion et al Appl. Phys. Express 12 070101 (2019)

Cavity spintronics

87

Cavity spintronics

Dany Lachance-Quirion et al Appl. Phys. Express 12 070101 (2019)

88

SC Qubit - magnon coupling

Y. Tabuchi, et al, Science 329, 405–408 (2015)

Kittel mode

Cavity mode

Cavity spintronics

89Y. Tabuchi, et al, Science 329, 405–408 (2015)


Cavity spintronics

90Y. Tabuchi, et al, Science 329, 405–408 (2015)


Cavity spintronics

91

Cavity Spintronics Gets More with Less

Can-Ming Hu, Physics 12, 97 (2019)

silicon substrate

microwave cavity

magnetic stripe

Cavity spintronics

92

Nb superconducting resonator

Cavity spintronics

Justin T. Hou and Luqiao Liu, Phys Rev Lett.123.107702 (2019)

93Justin T. Hou and Luqiao Liu, Phys Rev Lett.123.107702 (2019)

Strong magnons and photons coupling

Cavity spintronics

94Yi Li, et al, PRL.123.107701(2019)

Cavity spintronics

95

Summary






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Superconductor Spintronics - phy.pku.edu.cn