The low-field Hall mobility of an amorphous Hubbard model

Abstract

We study the low-field Hall conductivity of a structurally disordered Hubbard model near half-filling and in the strong-correlation limit. The electronic transfer integral is taken to have a quasi-exponential form. We use a diagrammatic method to calculate the required current correlation function to second order in the inverse temperature and up to the eighth order in the electronic hopping. A positive Hall coefficient is obtained. The Hall mobility μH is calculated for various atomic concentrations at high temperatures. We find that μH is larger than the corresponding drift mobility μD. In contrast to the results obtained for the case of nearest-neighbor hopping on a simple cubic lattice, the Hall mobility of our model shows a weak thermal variation at high temperatures, but the ratio μH/μD increases approximately linearly with temperature. These differences are discussed.