Effect of nonlocal charge correlations on the Mott-Hubbard transition

Max-Planck-Institut für Physik komplexer Systeme Nöthnitzer Straße 38, D-01187 Dresden, Germany

Received: 29 January 1999
Accepted: 8 July 1999

Abstract

The Mott-Hubbard transition is studied by examining the metal-insulator transition (MIT) in the homogeneous phase of the two-dimensional spinless Falicov-Kimball model. We use an extension of dynamical mean-field approximation, which allows inclusion of nonlocal correlations. The extension is based on the projection technique and the dynamical mean-field approximation, in which nonlocal contributions to the dynamics of systems are taken into account through static quantities, while the dynamical local contributions are kept by the memory function. We investigate critical behaviours of various dynamic and thermodynamic quantities near the MIT and estimate their critical exponents. The critical exponents obtained support a hyperscaling hypothesis and show a significant influence of nonlocal charge correlations on the transition.