Mechanisms of conventional and high Tc superconductivity

Contents......Page 12
1.1 Major goals......Page 18
1.2 Historical perspective......Page 19
2.1.1 The Hamiltonian......Page 21
2.1.2 Adiabatic approximation. \"Crude\" approach......Page 22
2.1.3 Electron–phonon coupling......Page 25
2.1.4 Superconductivity as a nonadiabatic phenomenon......Page 28
2.2.1 Self-energy parts......Page 29
2.2.2 General properties of the Eliashberg equations......Page 32
2.3.1 Weak coupling......Page 35
2.3.2 Intermediate coupling (λ[omitted]1.5)......Page 37
2.3.3 Coulomb interaction......Page 39
2.3.4 Very strong coupling......Page 40
2.3.5 General case......Page 42
2.4 Properties of superconductors with strong coupling......Page 45
2.5 Electron–phonon interaction and renormalization of normal parameters......Page 49
2.6.1 Phonon dynamics of perovskites......Page 52
2.6.2 Anharmonicity......Page 54
2.6.3 Bipolaronic superconductivity and negative Hubbard U-models......Page 56
2.7 Isotope effect......Page 57
3.1.1 Experimental methods......Page 59
3.1.2 Energy gap and transition temperature......Page 61
3.1.3 Inversion of the gap equation and α[Sup(2)]F(Ω)......Page 63
3.1.4 Electron–phonon coupling parameter λ......Page 65
3.2 Infrared spectroscopy......Page 67
3.3 Ultrasonic attenuation......Page 69
3.4 Nuclear magnetic resonance......Page 70
4.1 The Little model......Page 73
4.3 Excitons and high T[Sub(c)]......Page 76
4.4.1 Pairing of conduction electrons via interaction with localized states......Page 77
4.4.2 Two delocalized groups......Page 78
4.5 Negative U-centers......Page 79
4.6.1 Overlapping bands. \"Demons\"......Page 80
4.7 Coexistence of phonon and electronic mechanisms......Page 83
5.1 Introduction......Page 86
5.1.1 Localized vs. itinerant aspects of the cuprates......Page 87
5.2.1 The spin bag model of Schrieffer, Wen, and Zhang......Page 90
5.2.2 The t–J model......Page 93
5.2.3 Two-dimensional Hubbard model studies by Monte Carlo techniques......Page 98
5.2.4 Spiral phase of a doped quantum antiferromagnet......Page 107
5.2.5 Slave bosons......Page 112
5.3.1 The resonant valence bond (RVB) model and its evolution......Page 115
5.3.2 Anyon models and fractional statistics......Page 116
5.4 Conclusions......Page 117
6.1.1 General description......Page 118
6.1.2 Critical temperature......Page 119
6.1.3 Two-gap spectrum and properties of superconductors......Page 121
6.1.4 Induced two-band superconductivity......Page 122
6.2.1 Proximity \"sandwich\"......Page 123
6.2.2 Critical temperature. Induced energy gap......Page 124
6.3 Proximity effect vs. the two-gap model......Page 127
6.4.1 Hamiltonian. General equations......Page 128
6.4.2 Critical temperature......Page 131
6.4.3 Spectroscopy......Page 138
6.4.4 Magnetic impurities. Gapless induced superconductivity......Page 140
6.4.6 Conventional superconductors......Page 141
7.1 Introduction......Page 143
7.2.1 One-particle excitations......Page 144
7.2.2 Collective excitations......Page 148
7.3.1 Coherence length......Page 152
7.3.3 Critical behavior......Page 153
7.3.4 Positron annihilation......Page 154
7.3.5 Electromagnetic properties......Page 155
7.4 Induced superconducting state and two-gap structure......Page 157
7.4.1 Two-gap structure. Coherence lengths......Page 158
7.4.2 Oxygen depletion and the gapless state......Page 159
7.5 Origin of high T[Sub(c)]......Page 161
7.5.1 Determination of carrier-phonon coupling parameter......Page 162
7.5.2 Critical temperature......Page 164
7.5.3 Discussion......Page 165
7.6.1 Normal properties......Page 166
7.6.2 Superconducting properties......Page 168
7.6.3 Properties as a function of doping......Page 171
7.7.1 Why is T[Sub(c)] still so low in the organics?......Page 174
7.7.2 Superconducting fullerenes......Page 176
7.8 Future directions......Page 179
References......Page 181
H......Page 194
S......Page 195
Z......Page 196