Towards Room Temperature Tc Lessons from the “115” Materials APS March... · ~ 50 copper oxide superconductors Highest Tc = 164 K under pressure (1/2 Room Temp) Only class of

Towards Room Temperature Tc:

Lessons from the “115” Materials

John Sarrao

LANL

Outline

• An advertisement:

“Basic Research Needs for Superconductivity”

• Towards Room Temperature Tc

CeIn3 CeCoIn5 PuCoGa5 ?? (f/d)a(M,M‟)b(X,X‟)c

(200 mK) (2.3 K) (18.5 K) (~200 K)

• Examples

CeM2X2

“115” NpPd5Al2 (Aoki et al.)

• Towards material as an implicit parameter

Structures that “like” to superconduct

Role of electronic anisotropy, spin fluctuation scale

Basic Energy Sciences BES Report on Basic Research Needs for Superconductivity

http://www.sc.doe.gov/bes/reports/abstracts.html#SC

BES Workshop Report

Electricity is our most effective energy carrier • Clean, versatile, switchable power anywhere

Power grid cannot meet 21st century challenges• Capacity, reliability, quality, efficiency

Superconducting technology is poised to meet the challenge

Present generation materials enable grid connected cables and demonstrate control technology

Basic and applied research needed to lower cost and raise performance

High risk-high payoff discovery research for next-generation superconducting materials

• Higher temperature and current capability• Understand fundamental phenomena of

transition temperature and current flow




Superconductivity Research Continuum

Technology Maturation& Deployment

Applied Research

Cost reduction

Scale-up research

Prototyping

Manufacturing R&D

Deployment support

Discovery Research Use-inspired Basic Research

Office of Science

BES

Technology Offices

EDER

Technology Milestones:

2G coated conductor

carrying 300 A x 100 m

(2006)

In-field performance for

50 K operating

temperature

electric power equipment

with ½ the energy losses

and ½ the size

wire with 100x power

capacity of same size

copper wires at

$10/kiloamp-meter.

Assembly and utilization

R&D issues

Materials compatibility &

joining issues

Room-temperature

superconductor (Grand

Challenge)

Superconductors by design

(Grand Challenge)

Atomic scale control of

materials structure and

properties

Tuning competing interactions

for new phenomena

Unravel interaction functions

generating high temperature

superconductivity

Predictive understanding of

strongly correlated

superconductivity

Microscopic theory of vortex

matter dynamics

Nano-meso-scale

superconductivity

100K isotropic SC (Grand

Challenge)

Achieve theoretical limits of

critical current (Grand

Challenge)

3-d quantitative

determination of defects

and interfaces

Intrinsic and intentional

inhomogeneity

“Pinscape engineering” and

modeling of effective

pinning centers

Next Generation SC wires



Next Generation Materials

~ 50 copper oxide superconductors

Highest Tc = 164 K under pressure

(1/2 Room Temp)

Only class of high Tc superconductors ?

High Tc superconductors > 4 elements

55 superconducting elements

-> 554 ~ 10 million quaternaries

Search strategies for new superconductors• Quaternary and higher compounds

• Layered structures

• Highly correlated normal states

• Competing high temperature ordered phases

Liquid

Helium

Liquid

Hydrogen

Liquid

Neon

Surface

of Pluto

Liquid

Nitrogen

Night on

the moon

Ca @ 161 GPa

Challenge

Discover next generation complex superconductors

Target Properties Higher Tc &

JcisotropyDuctility

…



Superconductors by Design

Discovery by serendipity: Hg (1911), copper oxides (1986), MgB2 (2001), NaCoO2:H2O (2003)

Discovery by empirical guidelines: competing phases, layered structures, light elements, . . . B-doped diamond (2004), CaC6 (2005)

+ + =

Crystal StructureComposition

Electronic StructureDensity functional theory

Pairing Mechanismphonons (classical BCS)

spin fluctuationsvalence fluctuations

Tem

pera

ture

SC

Composition

Computationally designed superconductors

• Electronic structure calculation by density functional theory

• Large scale phonon calculations in nonlinear, anharmonic limit

• Formulate “very strong” electron-phonon coupling (beyond Eliashberg)

• Determine quantitative pairing mechanisms for high temperature SC

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

J. Mater. Chem., 2006

Computed metal hydridesuperconductor

Superconductivity

Challenge: Create a paradigm shift to superconductors by design

Known Heavy Fermion Superconductors

1980 1985 1990 1995 2000 20050.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Tc (K

)

year

CeCu2Si

2

UBe13

/LANL

UPt3/LANL

CeRhIn5 &

CeCoIn5/LANL

URu2Si

2

UPd2Al

3

UNi2Al

3

CeIrIn5/LANL

Tc/5

PuCoGa5/LANL

PuRhGa5

CeIn3

CePd2Si2

Growing number of HF SCs in

recent years:

The originals:

UBe13, UPt3, URu2Si2,

UNi2Al3, UPd2Al3

Nearly ferromagnetic:

UGe2, URhGe

Nearly antiferromagnetic:

CeCu2Si2 and related

CeRhIn5 and related

PuCoGa5, PuRhGa5, NpPd5Al2

PrOs4Sb12, CePt3Si, …

CeM2X2

(blue) Ce

(yellow) M=Cu, Pd, Rh

(gray) X=Si, Ge

Steglich

(1979)

CeM2X2 – Pressure Tuning

Holmes, PRB (04)

CePd2Si2

CeIn3

Mathur, Nature (1998)

CeMIn5

M = Co, Rh, Ir (isovalent)

A layered version of CeIn3?

CeRhIn5: 3.8 K AFM

CeCoIn5: 2.3 K SC

CeIrIn5: 0.4/1.0 K SC

12

10

8

6

4

2

0

T(K

)

100806040200

P (kbar)

, CeIn3 (Mathur et al.)

, CeRhIn5 (Hegger et al.)

CeRhIn5 (Muramatsu et al.)

CeRhIn5=CeIn3 + 13 kbar

CeCoIn5 (Nicklas, Sidorov et al.)

CeCoIn5=CeRhIn5+15 kbar

TN

Tc

CeMIn5 – Pressure Tuning

0 1 2 3 4 5 60.0

0.2

0.4

0.6

0.8

1.0

Tc/T

cm

ax

P (GPa)

CeRhIn5

CeIrIn5

CeCoIn5:P+1.6 GPa

1.610 1.615 1.620 1.625 1.630 1.635 1.6400.0

0.5

1.0

1.5

2.0

2.5

CeRhIn5 (~ 16 kbar)

CeCo0.5

Rh0.5

In5

CeCo0.5

Ir0.5

In5

CeRh0.5

Ir0.5

In5

CeRh0.25

Ir0.75

In5

CeIrIn5

CeCoIn5

Tc

c/a0

1

2

3

4

?SC

SCSC

X

0.50.50.5 IrRh CoCo

AFM

T* (

K)

CeCoIn5 CeRhIn5 CeIrIn5 CeCoIn5

CeMIn5 – Chemical Substitution

Pagliuso et al., Phys. Rev. B 64 (2001) 100503(R)

PuMGa5

0 5 10 15 20 250

10

20

30

40NFL

SC

n = 1.35

P (GPa)

PuCoGa5

0 1 2 3 4 51

2

3NFL

FLT

FL

Tpg

CeCoIn5

SC

n = 1.5

n 1

n = 2

0

5

10

15

20

25

NFL

SC

n = 1.35

PuRhGa5

T (

K)

PuCoGa5: 18.5 K SC

PuRhGa5: 9 K SC

1.610 1.615 1.620 1.625 1.630 1.635 1.6400.0

0.5

1.0

1.5

2.0

2.51.594 1.596 1.598 1.600 1.602 1.604

8

10

12

14

16

18

20

CeRhIn5 (~ 16 kbar)

CeCo0.5

Rh0.5

In5

CeCo0.5

Ir0.5

In5

CeRh0.5

Ir0.5

In5

CeRh0.25

Ir0.75

In5

CeIrIn5

CeCoIn5

Tc

c/a

PuCo.5Rh

.5Ga

5

c/a

Tc

PuCoGa5

PuRhGa5

Tc and c/a: anisotropy tuning

E.D. Bauer et al., PRL 93 (2004) 147005

Electronic Anisotropy: Quasi-2D Fermi Surface

R. Settai et al., JPCM 13, L627 (2001)

T. Maehira et al., PRL 90 (2003) 207007;

I. Opahle and P. M. Oppeneer, PRL 90 (2003) 157001

Experimentally, bulk properties (Hc2, r, c) have anisotropies of 3 - 5

Structural distortion: Crystal-field tuning

UMGa5: Kaneko, PRB 68 (2003)

Similar trends in NpMGa5

CeMIn5: Tc=1.6 + 56(2zc-a)/a

PuMGa5: Tc=28.4 + 790(2zc-a)a

(2zc-a)/a TN

UGa3 =0 65 K

UNiGa5 -1.5% 86

UPdGa5 -5.1% 30

UPtGa5 -7.0% 26

Ce3+

4f1

U3+

5f3

Pu3+

5f5

Np3+

5f4

-0.04 -0.03 -0.02 -0.01 0.00 0.01 0.020.0

0.5

1.0

1.5

2.0

2.5

0

4

8

12

16

20

PuCo0.1

Rh0.9

Ga5 CeCo

0.5Rh

0.5In

5

CeRh0.5

Ir0.5

In5

CeRh0.25

Ir0.75

In5

CeIrIn5

CeCoIn5

Tc (

K)

(2zc-a)/a

PuCo0.5

Rh0.5

Ga5

PuMGa5

CeMIn5

Tc (K

)

PuCoGa5

PuRhGa5

PuCoGa5: Tuning spin fluctuations?

(Tsf estimated from C/T for f-electron materials

and from T-linear resistivity of cuprates--Moriya and Ueda)

N. J. Curro et al., Nature 434, 622 (2005). 10 100 1000 100000.1

1

10

100

1000

CeCoIn5

CeRhIn5

CeCu2Si

2

UNi2Al

3

URu2Si

2

UPd2Al

3

UPt3

UBe13

U6Fe

UGe2

URhGe

HgBa2Ca

2Cu

3O

8+

Tl2Ba

2Ca

2Cu

3O

10

YBa2Cu

3O

7

La1.85

Sr0.15

CuO4

PuRhGa5

PuCoGa5

Tc (K

)

Tsf (K)

after T. Moriya and K. Ueda, Rep. Prog. Phys. 66, 1299 (2003)

Model Calculations – Combining Effects

Monthoux & Lonzarich PRB (02)

Model:

at = 0, quasi-2d electronic structure

= 1, cubic lattice

at = 0, quasi-2d magnetic correlations

= 1, 3d magnetic correlations

Similar contours for varied coupling constants

Tc(nearly AFM) ~ 10x Tc(nearly FM)

Experimentally,

Tc/Tsf ~ 0.05 – 0.1, CeCoIn5 or PuCoGa5

Increasing Anisotropy -Alternate stacking of 115

Ce2MIn8

- intermediate between CeIn3 & CeMIn5

-Ce-In no longer constrained to be co-planar

- sample quality less good due to stacking integrowths

Ce2RhIn8: 2.8 K AFM 2K SC

Ce2IrIn8: heavy-fermion Pauli paramagnet

Ce2CoIn8: ~ 0.8 K SC

Consider bi-layers of “MIn2” and CeIn3

-“CeM2In7” ???

And same for Pu analogs

-Pu2RhGa8 orders antiferomagnetically

Tuning spin fluctuations (too far) - UMGa5

250

200

150

100

50

0

r (

cm

)

300250200150100500

T(K)

60

50

40

30

20

10

0

r(

cm

)

CeCoIn5 (right axis)

PuCoGa5 (left)

UCoGa5 (left)

0.0 0.2 0.4 0.6 0.8 1.0 1.20.0

0.2

0.4

0.6

0.8

1.0

1.2

r(T

)r(T

ma

x)

T/Tmax

CeCoIn5

AMGa5

(A=U, Pu; M=Co, Rh)

0 200 400 600 8000.00

0.02

0.04

-1 (

mol-K

/mJ)

Tmax

(K)

Tsf a T

max a 1

Yb-115 and Np-115

Yb3+ (4f13): hole analog of Ce3+ (4f1)

YbMIn5 (M=Co, Rh, Ir) – good metals; divalent Yb

Pressure-induced magnetism/superconductivity??

NpMGa5

(U, Np, Pu, Am)

Studied extensively by Onuki group

Localized magnets, no superconductivity

NpPd5Al2 (Aoki et al., JPSJ 76 (2007) 063701)

Apparent “parent compound” NpPd3??

Nellis (1974)

Other transuranic compounds

Np, Pu intermetallics

• partially localized 5f electrons

• relatively unexplored phase space

Extensions to d electron metals?

Summary

Certain crystal structures „like‟ to superconduct

Can we calculate what‟s special about ThCr2Si2 and HoCoGa5

structure types?

Plausible relation among CeIn3 CeCoIn5 PuCoGa5

Optimistically (Naively?), perhaps there‟s another factor of

10 to be found through a directed random walk

Questions

Documents

Towards Room Temperature Tc Lessons from the “115” Materials APS March... · ~ 50 copper oxide superconductors Highest Tc = 164 K under pressure (1/2 Room Temp) Only class of