Vertex correction to pairing at a Van Hove singularity

Journal Article · Tue Feb 01 04:00:00 EST 1994 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.49.3520· OSTI ID:5222498

Krishnamurthy, H R; Newns, D M; Pattnaik, P C; Tsuei, C C; Chi, C C ^[1]

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1. IBM Research Division, Thomas J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York 10598 (United States)

We calculate in a [ital k]-averaging approximation, the vertex corrections for pairing at a Van Hove singularity mediated by an Einstein phonon. The vertex correction leads to a modest reduction in [ital T][sub [ital c]], which can still reach the experimental values for realistic phonon couplings, and to a significant deepening of the dip in the isotope shift at the [ital T][sub [ital c]] maximum. Interference between first- and second-order vertex graphs diminishes the effect of the Coulomb interaction on [ital T][sub [ital c]]. The isotope-shift dip is shallower for repulsive Coulomb interaction, and deeper in the case of an attractive interaction introduced to model an excitonic contribution to pairing.

• OSTI ID: 5222498
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 49:5; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

665411* -- Basic Superconductivity Studies-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COUPLING
ELECTRON-PHONON COUPLING
EXCITONS
FUNCTIONS
GORKOV-ELIASHBERG THEORY
GREEN FUNCTION
HIGH-TC SUPERCONDUCTORS
INTERACTIONS
NUMERICAL SOLUTION
PAIRING INTERACTIONS
QUASI PARTICLES
SINGULARITY
SUPERCONDUCTORS