文档介绍：The Grand Challenges
High Temperature Superconductivity in
Cu Oxides (1986 - )
Mechanism ?
Higher Tc ? :
“Is room-temperature superconductivity possible?”
ICAM05, Santa Fe, Nov. 12, 2005
1986
1993
1973
Tc vs year
Superconducting Tc (K)
Liq. N2
Liq. H2
Liq. He
1970
1980
1990
2000
2010
200
0
100
year
Tc (K)
1973
1986
1993
2006
Nb3Ge
LaBaCuO
YBaCuO
HgBaCaCuO
TlBaCaCuO
135K
23K
?
?
164K under high P
Future
Room-Temperature Superconductor
150
100
50
MgB2, Bi1-xKxBiO3,
C60, HfNCl
23K (Nb3Ge, 1973)
0
Tc (K)
Cuprates
Room-Temperature Superconductor
Perovskite (3D)
K2NiF4 (2D)
Materials
Bednorz & Mueller
square lattice
Doping
What makes the CuO2 plane unique
2 dimensions
Degenerate Cu 3dx2-y2-O2ps
S =1/2
Chain cuprate
High-Tc cuprates
Sr14Cu24O41
Sr2CuO3
Cubic cuprate (perovskite)
LaCuO3
LaCuO3 (3D)
Non-SC metal
Good metal, but non-SC
Sr2CuO3 (1D)
Doping is difficult.
undoped ladder
pressure
hole density
TcMAX~12K
//
// legs
// rungs
Thermal conductivity
Good thermal conductor
Electric insulator
SC
Motoyama / Buechner