Abstract
Motivated by superconductivity (SC) in layered nitrides, we study an ionic-Hubbard model of a honeycomb lattice, which consists of two sublattices with an energy-level offset, by an optimization variational Monte Carlo method. The parameters for the Coulomb interaction and energy-level offset to realize a band insulator in the nondoped state are evaluated, and the SC state is investigated in a carrier-doped band insulator. It is found that, in a weakly doped band insulator, spin fluctuation remains and the spin-singlet d-wave SC state is realized. Present results support an unconventional spin-singlet SC state suggested by the experimental observations in layered nitrides.
| Original language | English |
|---|---|
| Article number | 034704 |
| Journal | journal of the physical society of japan |
| Volume | 82 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 2013 Mar |
Keywords
- Band insulator
- Ionic-Hubbard model
- Mott insulator
- Nitride
- Superconductivity
- Variational Monte Carlo method
ASJC Scopus subject areas
- Physics and Astronomy(all)