Pressure-Temperature Phase Diagram of Generalized Hubbard Model with Correlated Hopping at Half-Filling

Abstract

In the present paper pressure-temperature phase diagram of a generalized Hubbard model with correlated hopping in a paramagnetic state at half-filling is determined by means of the generalized mean-field approximation in the Green function technique. The constructed phase diagram describes metal-to-insulator transition with increasing temperature, and insulator-to-metal transition under the action of external pressure. The phase diagram can explain paramagnetic region of the phase diagrams of some transition metal compounds. We have found that taking into account correlated hopping allows much better description of these experimental data than the Hubbard model; this testifies also much better physics of the present model and the important role of correlated hopping.