TY - JOUR
T1 - Superconducting states in a two-orbital Hubbard model on a triangular lattice
AU - Kobayashi, Kenji
AU - Yokoyama, Hisatoshi
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2007/3
Y1 - 2007/3
N2 - As a model of the novel superconductor Nax CoO2 · y H2 O, we study a triangular Hubbard model with doubly degenerate atomic orbitals, using an optimization variational Monte Carlo method. It is found that when the isolated Fermi surface overlaps the van Hove singularity points, dx2 - y2 and d + i d-wave superconducting states, among various pairing symmetries, become stabilized by large Coulomb interactions. The pairing is originating from the interaction-energy gain induced dominantly by the enhancement of antiferromagnetic spin correlations. The possibility of triplet pairing is limited for the present parameterization.
AB - As a model of the novel superconductor Nax CoO2 · y H2 O, we study a triangular Hubbard model with doubly degenerate atomic orbitals, using an optimization variational Monte Carlo method. It is found that when the isolated Fermi surface overlaps the van Hove singularity points, dx2 - y2 and d + i d-wave superconducting states, among various pairing symmetries, become stabilized by large Coulomb interactions. The pairing is originating from the interaction-energy gain induced dominantly by the enhancement of antiferromagnetic spin correlations. The possibility of triplet pairing is limited for the present parameterization.
KW - Hubbard model
KW - Pairing symmetries
KW - Transition-metal oxides
KW - Variational method
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U2 - 10.1016/j.jmmm.2006.10.107
DO - 10.1016/j.jmmm.2006.10.107
M3 - Article
AN - SCOPUS:33847278950
SN - 0304-8853
VL - 310
SP - 651
EP - 653
JO - Journal of Magnetism and Magnetic Materials
JF - Journal of Magnetism and Magnetic Materials
IS - 2 SUPPL. PART 1
ER -