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

Abstract

In the present paper, the pressure-temperature phase diagram of a generalized Hubbard model with correlated hopping in a paramagnetic state at half-filling is determined by means of a generalized mean-field approximation in the Green function technique. The constructed phase diagram describes the metal-to-insulator transition with increasing temperature, and the insulator-to-metal transition under the action of external pressure. The phase diagram can explain the paramagnetic region of the phase diagrams of some transition metal compounds.

Electron Correlations in Narrow Energy Bands: Ground State Energy and Metal-Insulator Transition

“…The dependence obtained can qualitatively explain the transitions from metallic to insulating state with the increase of temperature in the systems NiS 2−x Se x , (V 1−x Cr x ) 2 O 3 and Y 1−x Ca x TiO 3 ) experimentally observed in a paramagnetic state. Note that the quantitative description of the pressuretemperature phase diagram of these compounds within the generalized Hubbard model with correlated hopping has been done in [24].…”