Phase Transition and Spatial Correlation of Localized States in the Falicov‐Ramírez‐Kimball Model

Abstract

The Falicov‐Ramirez‐Kimball model is solved by means of the two‐atom cluster Caron‐Pratt approximation. Metallic and insulating phases according to the value of an order parameter Δ are obtained, and both second‐ and first‐order phase transitions between them. Two kinds of insulating solutions (ordinary and mixed valence) and a variety of metallic states with different inter‐ionic degrees of correlation are obtained. These results are found to be inqualitative accord both with experiments and former theoretical treatments. Copyright © 1981 WILEY‐VCH Verlag GmbH & Co. KGaA