  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 Non-Linear Sigma Model treatment in d = (2 + epsilon) > 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.
