Electronic phase transitions in the spinless Falicov-Kimball model

Abstract

The spinless Falicov-Kimball model for electronically driven metal-insulator and valence transitions is studied using exact numerical calculations. It is shown that in the pressure induced case the model undergoes a few (discrete) intermediate valence transitions, while valence transitions as a function of temperature are always continuous. We demonstrate that these results are independent of finite-size effects. Interesting consequences of this picture of valence changes can be found furthermore under the assumption that thef-level position may fluctuate (due to some additional interactions) about its average value. Then the model is capable to describe a transition from an inhomogeneous intermediate valence state into a homogeneous intermediate valence state as well as the semiconductor-metal transition.