Theory of High Temperature Superconductivity

1. Front Matter

   Pages i-xix

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2. Introduction

   Pages 1-18

3. Superconducting Transition

   Pages 19-25

4. Bloch Electrons

   Pages 27-44

5. Phonon-Exchange Attraction

   Pages 45-58

6. Quantum Statistical Theory

   Pages 59-63

7. Cooper Pairs (Pairons)

   Pages 65-76

8. Superconductors at 0 K

   Pages 77-93

9. Quantum Statistics of Composites

   Pages 95-106

10. Bose-Einstein Condensation

    Pages 107-121

11. The Energy Gap Equations

    Pages 123-132

12. Pairon Energy Gaps. Heat Capacity

    Pages 133-146

13. Quantum Tunneling

    Pages 147-161

14. Flux Quantization

    Pages 163-180

15. Ginzburg-Landau Theory

    Pages 181-191

16. Josephson Effects

    Pages 193-206

17. Compound Superconductors

    Pages 207-216

18. Lattice Structures of Cuprates

    Pages 217-225

19. High-Tc Superconductors Below Tc

    Pages 227-239

20. Doping Dependence of T _c

    Pages 241-248

Flux quantization experiments indicate that the carriers, Cooper pairs (pairons), in the supercurrent have charge magnitude 2e, and that they move independently. Josephson interference in a Superconducting Quantum Int- ference Device (SQUID) shows that the centers of masses (CM) of pairons move as bosons with a linear dispersion relation. Based on this evidence we develop a theory of superconductivity in conventional and mate- als from a unified point of view. Following Bardeen, Cooper and Schrieffer (BCS) we regard the phonon exchange attraction as the cause of superc- ductivity. For cuprate superconductors, however, we take account of both optical- and acoustic-phonon exchange. BCS started with a Hamiltonian containing “electron” and “hole” kinetic energies and a pairing interaction with the phonon variables eliminated. These “electrons” and “holes” were introduced formally in terms of a free-electron model, which we consider unsatisfactory. We define “electrons” and “holes” in terms of the cur- tures of the Fermi surface. “Electrons” (1) and “holes” (2) are different and so they are assigned with different effective masses: Blatt, Schafroth and Butler proposed to explain superconductivity in terms of a Bose-Einstein Condensation (BEC) of electron pairs, each having mass M and a size. The system of free massive bosons, having a quadratic dispersion relation: and moving in three dimensions (3D) undergoes a BEC transition at where is the pair density.

• Cooper pair
• Doping
• Hall effect
• Josephson effect
• Superconductor
• superconductivity
• transitions

• University at Buffalo, SUNY, Buffalo, USA

  Shigeji Fujita

• Universidad Nacional Autónoma de México, México, D.F., México

  Salvador Godoy

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