Two relaxation rates in the Hubbard-Falicov-Kimball Model

A single transport relaxation rate governs the decay of both, longitudinal and Hall currents in Landau Fermi Liquid (FL). Breakdown of this fundamental feature, first observed in cuprates and subsequently in other correlated systems close to (partial or complete) Mott metal-insulator transitions, played a pivotal role in emergence of a non-FL (NFL) paradigm in higher dimensions d > 1. Motivated hereby, we explore the emergence of this ``two relaxation rates'' scenario in the Hubbard-Falicov-Kimball model (HFKM) using the dynamical mean-field theory (DMFT). Specializing to d=3, we find, beyond a critical FK interaction, that two distinct relaxation rates governing distinct temperature dependence of the longitudinal and Hall currents naturally emerges in the NFL metal. Our results show good accord with the experiment in vandium sesquioxide near the metal-to-insulator transition (MIT). We rationalize this surprising finding by an analytical analysis of the structure of charge and spin Hamiltonians in the underlying impurity problem, specifically through a bosonization method applied to the Wolff model and connecting it to the x-ray edge problem.

Reference : https:// arxiv.org/abs/1611.07594 .