TY - JOUR
T1 - Stability of the superconducting state in the two-band Hubbard model on a triangular lattice
AU - Kobayashi, Kenji
AU - Yokoyama, Hisatoshi
PY - 2006/10/1
Y1 - 2006/10/1
N2 - As a model of the novel superconductor NaxCoO2 · yH2O, 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 + id-wave superconducting states, among various pairing symmetries, are appreciably stabilized by large Coulomb interactions. The pairing is originating from the potential energy gain induced dominantly by the enhancement of antiferromagnetic spin correlations. The possibility of triplet pairing is very slight in this model.
AB - As a model of the novel superconductor NaxCoO2 · yH2O, 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 + id-wave superconducting states, among various pairing symmetries, are appreciably stabilized by large Coulomb interactions. The pairing is originating from the potential energy gain induced dominantly by the enhancement of antiferromagnetic spin correlations. The possibility of triplet pairing is very slight in this model.
KW - Cobalt oxide
KW - Hubbard model
KW - Pairing symmetry
KW - Variational Monte Carlo method
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U2 - 10.1016/j.physc.2006.03.106
DO - 10.1016/j.physc.2006.03.106
M3 - Article
AN - SCOPUS:33748630756
SN - 0921-4534
VL - 445-448
SP - 162
EP - 165
JO - Physica C: Superconductivity and its Applications
JF - Physica C: Superconductivity and its Applications
IS - 1-2
ER -