Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1819324 | Physica C: Superconductivity and its Applications | 2009 | 5 Pages |
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 tâ², 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)-tâ²/t space, and find that for tâ²/t⩾-0.15 a coexisting state is realized, whose range of δ extends as tâ²/t increases. In contrast, for tâ²/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.
Keywords
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
Kenji Kobayashi, Hisatoshi Yokoyama,