Superconducting states in a two-orbital Hubbard model on a triangular lattice

Kenji Kobayashi, Hisatoshi Yokoyama

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish
Pages (from-to)651-653
Number of pages3
JournalJournal of Magnetism and Magnetic Materials
Issue number2 SUPPL. PART 1
Publication statusPublished - 2007 Mar


  • Hubbard model
  • Pairing symmetries
  • Transition-metal oxides
  • Variational method


Dive into the research topics of 'Superconducting states in a two-orbital Hubbard model on a triangular lattice'. Together they form a unique fingerprint.

Cite this