The spin-triplet superconductivity induced by the charge fluctuation in extended Hubbard model

Abstract

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 the square lattice with second-neighbor hopping t'. We have found that (i) for large U(>9) a triplet superconductivity with a sin(kx+ky) symmetry can appear just below the charge density wave phase. The pairing is degenerate with sin(kx-ky), so a chiral sin(kx+ky)+isin(kx-ky) that breaks the time reversal symmetry should result, which is a candidate for the gap function on the gamma band of Sr2RuO4 and is consistent with a recent measurement of the specific heat. (ii) By systematically deforming the Fermi surface with varied t', we have identified the region where the triplet pairing is most favored to be the region where the Fermi surface traverses the van Hove singularity with the charge susceptibility strongly enhanced.

7 pages, 12 figures

References in corpus (6)

• Gap Structure of the Spin-Triplet Superconductor Sr2RuO4 Determined from the Field-Orientation Dependence of Specific Heat
• Phase diagram of the two-dimensional extended Hubbard model: Phase transitions between different pairing symmetries when charge and spin fluctuations coexist
• Microscopic Identification of the D-vector in Triplet Superconductor Sr_2RuO_4
• Off-site-repulsion induced Triplet Superconductivity: a possibility of chiral p${}_{x+y}$ pairing in Sr${}_2$RuO${}_4$
• Quantum Monte Carlo study of the pairing symmetry competition in the Hubbard model
• Superconductivity in repulsive electron systems having three-dimensional disconnected Fermi surfaces

Cited by in corpus (6)

• Odd-frequency Superconductivity on a Quasi-one-dimensional Triangular Lattice in the Hubbard Model
• Microscopic theory of tunneling spectroscopy in Sr${}_2$RuO${}_4$
• Revisiting superconductivity in the extended one-band Hubbard model: pairing via spin and charge fluctuations
• Superconducting pairing symmetry on the extended Hubbard model in the presence of the Rashba-type spin-orbit coupling
• Exotic Superconductivity in the Extended Attractive Hubbard Model
• $d_{x^2-y^2}$-wave density wave and $d_{x^2-y^2}$-wave superconducting gap on the extended Hubbard model on a square lattice