Band and Mott Insulators and Superconductivity in Honeycomb-Lattice Ionic-Hubbard Model

Abstract

Motivated by superconductivity (SC) in layered nitrides, we study an ionic-Hubbard model on a honeycomb lattice, which consists of two sublattices with an energy-level offset, by using an optimization variational Monte Carlo method. Parameter values for the Coulomb interaction and the energy-level offset, to realize a band insulator in non-doped 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.

8 pages, 9 figures

References in corpus (1)

• Mott Transitions and d-wave Superconductivity in Half-Filled-Band Hubbard Model on Square Lattice with Geometric Frustration

Cited by in corpus (11)

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• Exploring competing density order in the ionic Hubbard model with ultracold fermions
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• Pairing and chiral spin density wave instabilities on the honeycomb lattice: a comparative quantum Monte Carlo study
• Possible singlet and triplet superconductivity on honeycomb lattice
• Disappearance of the Dirac cone in silicene due to the presence of an electric field
• Dispersive Excitations in the One-Dimensional Ionic Hubbard Model
• Superconductivity of repulsive spinless fermions with sublattice potentials
• Unconventional superconductivity in a strongly correlated band-insulator without doping
• Effects of correlations on honeycomb lattice in ionic-Hubbard Model
• Dynamical Charge Structure Factor of a One-Dimensional Ionic Hubbard Model in the Low-Energy Region