TY - JOUR
T1 - Spin-triplet superconductivity induced by charge fluctuations in extended Hubbard model
AU - Onari, Seiichiro
AU - Arita, Ryotaro
AU - Kuroki, Kazuhiko
AU - Aoki, Hideo
N1 - Copyright:
Copyright 2005 Elsevier B.V., All rights reserved.
PY - 2005/9
Y1 - 2005/9
N2 - The pairing symmetry in the electron mechanism for superconductivity is explored when charge fluctuations coexist with spin fluctuations. The extended Hubbard model is adopted to obtain, with the fluctuation exchange approximation, a phase diagram against the on-site Coulomb repulsion U and the off-site repulsion V for a square lattice with a second-neighbor hopping t′. We have observed the following. (i) For large U(> 9), a triplet superconductivity with sin(kx + ky) symmetry can appear just below the charge density wave phase. The pairing is degenerate with sin(kx - ky), so a chiral (kx + ky) + i sin(kx - ky) that breaks the time-reversal symmetry should result, which is a candidate for the gap function on the γ band of Sr2RuO4 and is consistent with a recent measurement of the specific heat. (ii) By systematically deforming the Fermi surface with varied t′, the region most favored by the triplet is identified to be the region where the Fermi surface traverses the van Hove singularity with the charge susceptibility strongly enhanced.
AB - The pairing symmetry in the electron mechanism for superconductivity is explored when charge fluctuations coexist with spin fluctuations. The extended Hubbard model is adopted to obtain, with the fluctuation exchange approximation, a phase diagram against the on-site Coulomb repulsion U and the off-site repulsion V for a square lattice with a second-neighbor hopping t′. We have observed the following. (i) For large U(> 9), a triplet superconductivity with sin(kx + ky) symmetry can appear just below the charge density wave phase. The pairing is degenerate with sin(kx - ky), so a chiral (kx + ky) + i sin(kx - ky) that breaks the time-reversal symmetry should result, which is a candidate for the gap function on the γ band of Sr2RuO4 and is consistent with a recent measurement of the specific heat. (ii) By systematically deforming the Fermi surface with varied t′, the region most favored by the triplet is identified to be the region where the Fermi surface traverses the van Hove singularity with the charge susceptibility strongly enhanced.
KW - Charge susceptibility
KW - Extended Hubbard model
KW - Spin susceptibility
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U2 - 10.1143/JPSJ.74.2579
DO - 10.1143/JPSJ.74.2579
M3 - Article
AN - SCOPUS:25144486748
VL - 74
SP - 2579
EP - 2585
JO - Journal of the Physical Society of Japan
JF - Journal of the Physical Society of Japan
SN - 0031-9015
IS - 9
ER -