Superconducting transition of 2D two-band systems with interband pair-transfer interaction

✍ Scribed by Kunihiko Yamaji

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 310 KB
• Volume: 165-166
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/s0921-4526(09)80090-2

✦ Synopsis

An interband BCS-type pair-transfer process arises from an off-diagonal matrix element of the Coulomb interaction. This is shown to be divergently intensified through a ladder-diagram process in a twodimensional (20) two-band systems with concentric circular electron and hole Fermi surfaces. This effect comes from a peak of the interband polarization function for the wave number equal to the difference of the wave numbers of the two bands; the peak can lead to the divergence of the above-mentioned ladderdiagram process, resulting in an s-wave superconductivity with T c possibly reaching 200 K despite large onsite Coulomb energies. This mechanism is argued to be substantiated in high-T c oxides.