Phase diagram of the three-dimensional Anderson model of localization with random hopping

Abstract. We examine the localization properties of the three-dimensional (3D) Anderson Hamiltonian with off-diagonal disorder using the transfer-matrix method (TMM) and finitesize scaling (FSS). The nearest-neighbor hopping elements are chosen randomly according to tij ∈ [c− 1/2, c+1/2]. We find that the off-diagonal disorder is not strong enough to localize all states in the spectrum in contradistinction to the usual case of diagonal disorder. Thus for any off-diagonal disorder, there exist extended states and, consequently, the TMM converges very slowly. From the TMM results we compute critical exponents of the metal-insulator transitions (MIT), the mobility edge Ec, and study the energy-disorder phase diagram.