Crossover of superconducting properties and kinetic-energy gain in two-dimensional Hubbard model

Hisatoshi Yokoyama, Yukio Tanaka, Masao Ogata, Hiroki Tsuchiura

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77 Citations (Scopus)

Abstract

Superconductivity in the Hubbard model on a square lattice near half filling is studied using an optimization (or correlated) variational Monte Carlo method. Second-order processes of a strong-coupling expansion are considered in wave functions beyond the Gutzwiller projection. Superconductivity of d x2-y2-wave symmetry is widely stable, and exhibits a crossover around U = Uco ∼ 12t from a BCS type to a new type. For U ≳ U co (U ≲ Uco), the energy gain in the superconducting state is derived from the kinetic (potential) energy. Condensation energy is large and ∝ exp(-t/J) [tiny] on the strong [weak] coupling side of U co. With reference to experiments on optical conductivity, cuprates belong to the strong-coupling regime.

Original languageEnglish
Pages (from-to)1119-1122
Number of pages4
Journaljournal of the physical society of japan
Volume73
Issue number5
DOIs
Publication statusPublished - 2004 May

Keywords

  • Antiferromagnetism
  • Condensation energy
  • Crossover
  • High-T cuprate
  • Hubbard model
  • Kinetic energy
  • Optical conductivity
  • Superconductivity
  • Variational Monte Carlo method

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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