The metal–insulator transition in the half-filled extended Hubbard model on a triangularlattice

Abstract

In this paper, we have investigated the metal–insulator transition (MIT) in atwo-dimensional half-filled extended Hubbard model on an isotropic triangularlattice with a real space block renormalization group technique. It has beenfound that the MIT can be driven nontrivially by either the on-site interactionU or thenearest-neighbor one V, but with different critical exponents. Depending upon the values ofV, the system could have one, two or three MIT critical points. Moreover, for the metallicregime, we have also studied the competition effect from the spin density wave and chargedensity wave phases by using a mean-field theory based upon Hartree–Fock approximations.Finally, the single-site entanglement is also calculated and its first derivative with respect toU shows a jump along the critical line of the MIT.