Interplay between antiferromagnetism and superconductivity in the Hubbard model with frustration

Kenji Kobayashi, Hisatoshi Yokoyama

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

Coexistence of and competition between antiferromagnetism (AF) and d-wave superconductivity (SC) are studied for a Hubbard model on the square lattice with a diagonal transfer t, using a variational Monte Carlo method. The following improvements are introduced into the trial function: (1) Coexistence of AF and d-wave singlet gaps that allows a continuous description of their interplay, (2) band renormalization effect, and (3) refined doublon-holon correlation factors. Optimizing this function for a strongly correlated value of U / t, we construct a phase diagram in the δ (doping rate)-t / t space, and find that for t / t ≥ - 0.15 a coexisting state is realized, whose range of δ extends as t / t increases. In contrast, for t / t = - 0.3, AF and SC states are mutually exclusive, and a coexisting state does not appear. In connection with the "two-gap" problem, we confirm even for the present refined function that the gradient of momentum distribution function at the antinodal point mainly dominates the magnitude of the d-wave SC correlation function.

Original languageEnglish
Pages (from-to)974-978
Number of pages5
JournalPhysica C: Superconductivity and its applications
Volume469
Issue number15-20
DOIs
Publication statusPublished - 2009 Oct 15

Keywords

  • Cuprate
  • Hubbard model
  • Superconductivity
  • Variational Monte Carlo method

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering

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