Physical review. B, Condensed matter
Exact results for the extended Anderson model with Falicov-Kimball interactions
L. G. Sarasúa, M. A. Contínentino
Abstract
We present exact results for the extended periodic Anderson model with Falicov-Kimball interactions in one dimension $(d=1).$ Ground-state energies and their corresponding wave functions are obtained for a restricted region of the parameter space of the model Hamiltonian. In particular, two ground states are obtained, one containing one electron per site and the other three electrons per site. The expectation values of the occupation numbers and of the excitonic correlation functions $〈{\mathrm{cf}}^{+}〉$ are calculated using the exact ground state wave functions. Finally we discuss the possibility of a ferroelectric ground state in the Falicov-Kimball model.