Spin-Triplet Superconductivity Induced by Charge Fluctuations in Extended Hubbard Model

• Onari Seiichiro

  Department of Physics, University of Tokyo

• Arita Ryotaro

  Department of Physics, University of Tokyo

• Kuroki Kazuhiko

  Department of Applied Physics and Chemistry, University of Electro-Communications

• Aoki Hideo

  Department of Physics, University of Tokyo

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 a square lattice with a second-neighbor hopping t′. We have observed the following. (i) For large U(>9), a triplet superconductivity with sin(k_x+k_y) symmetry can appear just below the charge density wave phase. The pairing is degenerate with sin(k_x−k_y), so a chiral sin(k_x+k_y)+isin(k_x−k_y) 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.

Journal

• Journal of the Physical Society of Japan

  Journal of the Physical Society of Japan 74 (9), 2579-2585, 2005

  THE PHYSICAL SOCIETY OF JAPAN

Keywords

• extended Hubbard model
• charge susceptibility
• spin susceptibility

Details

• CRID: 1390001204188175232
• NII Article ID: 110002245746
• NII Article ID: 210000105650
• NII Article ID: 130004539414
• NII Book ID: AA00704814
• DOI: 10.1143/jpsj.74.2579
• BIBCODE: 2005JPSJ...74.2579O
• ISSN: 13474073
• ISSN: 00319015
• NDL BIB ID: 7439606
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I7439606
• Web Site: http://journals.jps.jp/doi/pdf/10.1143/JPSJ.74.2579
• Text Lang: en
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed