Anderson localization in two-dimensional disordered systems

Using the transfer matrix method we have calculated the localization length in a 2D (two dimension) rectangular lattice with both on-site and off-diagonal disorder. Using finite size scaling we show that systems with off-diagonal disorder are much more sensitive to disorder than the system with on-site disorder, e.g. at the same amount of disorder (W = w = 2) the localization length for on-site disorder is 10(4) times longer than for off-diagonal disorder. We consider both isotropic and anisotropic systems, where the latter can be considered as a model for an organic crystal. In the anisotropic case the maximum localization length is at the band center, the isotropic system has a maximum away from the band center. (C) 2003 Elsevier Science B.V. All fights reserved.