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

. 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 t ij 2 [c \Gamma 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. Keywords: disorder, localization, metal-insulator transition, random hopping PACS: 71.30.+h, 72.15.Rn, 72.80.Ng 1 Introduction From the scaling hypothesis of localization [1] it is well known that in one (1D) and two dimensions (2D) almost all states of a non-interactin..