Abstract
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 language | English |
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Pages (from-to) | 651-653 |
Number of pages | 3 |
Journal | Journal of Magnetism and Magnetic Materials |
Volume | 310 |
Issue number | 2 SUPPL. PART 1 |
DOIs | |
Publication status | Published - 2007 Mar |
Keywords
- Hubbard model
- Pairing symmetries
- Transition-metal oxides
- Variational method
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics