J. Phys. Soc. Jpn. 74, pp. 2901-2904 (2005) [4 Pages]

Charge Order and Superconductivity in Two-Dimensional Triangular Lattice at n=2/3

+ Affiliations
1Department of Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033

To investigate the possibility of charge order and superconductivity in a doped two-dimensional triangular lattice, we study an extended Hubbard model with the variational Monte Carlo method. At n =2/3, a commensurate filling for a triangular lattice, it is shown that the nearest-neighbor Coulomb interaction V induces honeycomb-type charge order and antiferromagnetic spin order at \(U\gtrsim 10t\). We also discuss the possibility of superconductivity induced by charge fluctuation and the relation to the superconductivity in Na 0.35 CoO 2 ·1.3H 2 O and θ-type organic condoctors.

©2005 The Physical Society of Japan