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(Online) Anderson localization effects in the doped Hubbard model

Maria Carolina O. Aguiar, Department of Physics, Federal University of Minas Gerais, Brazil ; LPS Orsay

I will discuss the interplay between doping, disorder, and correlations in electronic systems. The increase of the interaction between electrons drives a system through a Mott metal-insulator transition, which can be described by the Hubbard model. An Anderson type of localization, on the other hand, takes place in the presence of strong disorder. By solving the disordered Hubbard model by extensions of dynamical mean field theory, we observe the so-called Mott-Anderson insulating phase. At half-filling, this is a mixture of Mott and Anderson insulators : it has doubly- and singly-occupied sites, as well as empty ones [1]. The presence of empty sites in the Mott-Anderson insulator gives rise to the formation of a V-shaped density of states (DOS) around the Fermi level. In the doped case, as doping and/or interaction increases, the empty sites become occupied and the V-shaped DOS is not observed anymore. For strong interactions values (in comparison with the clean, non-interacting DOS bandwidth), a large region of the disorder versus doping phase diagram corresponds to a Mott-Anderson insulator without a V-shaped DOS.
I will first review Mott and Anderson mechanisms of localization and then focus on our recent results for the disordered, doped Hubbard model.

[1] : M.C.O. Aguiar et al., Phys. Rev. Lett. 102, 156402 (2009).


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