|
We investigate the effects of weak and moderate disorder on the T=0 Mott Metal-Insulator Transition (MIT) in two dimensions, by solving the disordered Hubbard Model within the so-called Statistical Dynamical Mean Field Theory (statDMFT) [1]. In the weak disorder regime, we recover the results of the standard DMFT limit [2], including strong disorder screening close to the MIT. For moderate disorder, the screening of the disorder remains strong, but is reduced by fluctuation effects absent in high dimensions. For disorder strength W smaller then the on-site interaction U, the transition retains the Mott character, where the local quasiparticles weights Zi vanish on all sites at the transition, indicating the transmutation of all electron into local magnetic moments. In contrast to the behavior in high dimensions [2], the corresponding distribution function P(Z) is found to assume a singular form as the transition is approached, indicating the emergence of an electronic Griffiths phase [3] preceding the MIT.
[1] V. Dobrosavljevic and G. Kotliar, Phys. Rev. Lett. 78, 3943 (1997). [2] D. Tanaskovic et al, Phys. Rev. Lett. 91, 066603 (2003). [3] E. Miranda and V. Dobrosavljevic, Phys. Rev. Lett. 86, 264 (2001). |
|