High-Temperature Thermodynamics of the Strongly Correlated Hubbard Model at Arbitrary Electron Density

Abstract

We consider the Hubbard model for electron correlations in solids in the narrow-band regime where the intra-atomic Coulomb repulsion is large compared to the bandwidth. A high-temperature pertubation expansion in the bandwidth is performed to lowest order for the grand partition function. This procedure is carried out both for one-dimensional systems, of interest for the tetracyanoquinodimethan (TCNQ) charge-transfer salts, and for a three-dimensional cubic lattice. Both the specific heat and magnetic susceptibility are computed as functions of temperature and electron density.