Local pairs and small surfaces

Nature ◽  
2007 ◽  
Vol 447 (7144) ◽  
pp. 537-539 ◽  
Author(s):  
Stephen R. Julian ◽  
Michael R. Norman
Keyword(s):  
Local Pairs

ELECTRONIC TRANSFER OF LOCAL PAIRS AND SUPERCONDUCTIVITY IN METAL OXIDE COMPOUNDS

1988 ◽  
Vol 02 (05) ◽  
pp. 851-865 ◽  
Author(s):  
I. O. KULIK
Keyword(s):  
Kinetic Energy ◽  
Oxygen Atom ◽  
Metal Oxide ◽  
Conduction Band ◽  
Normal State ◽  
Tunneling Effect ◽  
Ir Absorption ◽  
Pair Condensation ◽  
Local Pair ◽  
Local Pairs

We propose that two-electron centers (local pairs) are formed at oxygen atom(s) which preexist superconductivity. Due to the interaction of these with the conduction band electrons (presumably those at Cu – O layers) the local pairs (which are supposed to be peroxide species, [Formula: see text], in perovskite high-Tc compounds) gain kinetic energy and become mobile. Superconductivity scenario is that of local pair condensation accompanied by BCS-like ordering of conduction band electrons. Consequences of the model concerning gap (or, rather, gaps) formation, pecularities of IR absorption and tunneling effect, and transport properties in the normal state are discussed.

scholarly journals On Local Pairs vs. BCS: Quo Vadis High- T c Superconductivity

2016 ◽  
Vol 30 (3) ◽  
pp. 731-734 ◽  
Author(s):  
D. Pavuna ◽  
G. Dubuis ◽  
A. T. Bollinger ◽  
J. Wu ◽  
X. He ◽  
...  
Keyword(s):  
Quo Vadis ◽  
Local Pairs

SUPERCONDUCTIVITY OF SYSTEMS WITH COEXISTING ITINERANT ELECTRONS AND LOCAL PAIRS

2001 ◽  
Vol 15 (23) ◽  
pp. 3125-3142 ◽  
Author(s):  
WOJCIECH R. CZART ◽  
STANISŁAW ROBASZKIEWICZ
Keyword(s):  
Phase Diagrams ◽  
Linear Response ◽  
Linear Response Theory ◽  
Real Space ◽  
Electromagnetic Properties ◽  
Site Density ◽  
Itinerant Electrons ◽  
Interaction Term ◽  
Local Pair ◽  
Local Pairs

Phase diagrams and electromagnetic properties of the system of coexisting itinerant (c)-electrons and localized (d)-electrons which can form real space local pairs are analyzed. The model considered assumes arbitrary value of the on-site density interaction of d-electrons U d , which allows investigation of the effects of reduced d-pair binding energy. The phase diagrams of the system have been evaluated within the approach which treats the on-site interaction term U d exactly and the remaining interactions within the broke symmetry HFA. Within the linear response theory the electromagnetic kernels are calculated and basic superfluid characteristics of the system are determined as a function of electron concentration, interactions and relative position of the bands. Depending on parameters the model is found to exhibit several kinds of superconducting behaviors ranging from the BCS-like to the local pair-like. The relevance of obtained results to the interpretation of experimental data for short-coherence length superconductors is pointed out.

Anisotropic superconductivity in systems with coexisting electrons and local pairs

2002 ◽  
Vol 66 (10) ◽  
Author(s):  
R. Micnas ◽  
S. Robaszkiewicz ◽  
A. Bussmann-Holder
Keyword(s):  
Anisotropic Superconductivity ◽  
Local Pairs

Superconductivity of a mixture of local pairs and quasi free electrons

1988 ◽  
Vol 13 (5) ◽  
pp. 455-464 ◽  
Author(s):  
J. Ranninger ◽  
R. Micnas ◽  
S. Robaszkiewicz
Keyword(s):  
Free Electrons ◽  
Local Pairs

Transport of local pairs in metallic oxides: Calculation of the frequency and temperature dependence of the conductivity

1991 ◽  
Vol 44 (18) ◽  
pp. 10215-10221 ◽  
Author(s):  
Robert I. Shekhter ◽  
Göran Wendin ◽  
Igor O. Kulik
Keyword(s):  
Temperature Dependence ◽  
Metallic Oxides ◽  
Local Pairs

THERMOELECTRIC POWER AND HALL EFFECT OF HIGH-Tc SUPERCONDUCTORS IN A TWO-COMPONENT MODEL

2001 ◽  
Vol 15 (03) ◽  
pp. 89-96
Author(s):  
SHUANG ZHANG ◽  
LI-YUAN ZHANG ◽  
XIAO-QIANG YANG
Keyword(s):  
Hall Effect ◽  
Thermoelectric Power ◽  
Normal State ◽  
Correlation Energy ◽  
Component Model ◽  
High Tc Superconductors ◽  
High Tc ◽  
Two Component ◽  
Local Pair ◽  
Local Pairs

In this paper we have succeeded in describing the thermoelectric power and the Hall coefficient in the normal state of several underdoped and nearly optimally doped high-T c superconductors within the framework of the two-subsystem (or two-component) model. We analyze the effect of pseudogap on Hall effect and get the temperature T* at which the pseudogap opens. The results agree with those of experiments. The correlation energy of the nearly local pair is in the same order of the magnitude with thermal energy (k B T), so the pairs have somewhat decomposability, therefore, we suggest that the nearly local pairs coexist with itinerant single carriers in the normal state of high-T c superconductors.

From BCS-like superconductivity to condensation of local pairs: A numerical study of the attractive Hubbard model

1996 ◽  
Vol 54 (2) ◽  
pp. 1286-1301 ◽  
Author(s):  
J. M. Singer ◽  
M. H. Pedersen ◽  
T. Schneider ◽  
H. Beck ◽  
H.-G. Matuttis
Keyword(s):  
Hubbard Model ◽  
Numerical Study ◽  
Attractive Hubbard Model ◽  
Local Pairs
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