Metal-insulator transition in Hubbard-like models with random hopping

Abstract

An instability of a diffusive Fermi liquid, indicative of a metal-insulator transition (expected to be of first order), arising solely from the competition between quenched disorder and short-ranged interparticle interactions is identified in Hubbard-like models for spinless fermions, subject to (complex) random hopping at half filling on bipartite lattices. The instability, found within a Finkel'stein nonlinear $\ensuremath{\sigma}$ model treatment in $d=(2+ϵ)>2$ dimensions, originates from an underlying particle-hole-like (so-called chiral) symmetry, shared by both disorder and interactions. In the clean, interacting Fermi liquid this symmetry is responsible for the (completely different) nesting instability.