Typical Medium Dynamical Cluster Approximation - 848 Words

We generalize the typical medium dynamical cluster approximation (TMDCA) for systems with off-diagonal disorder. By applying our approach to the Anderson model we consider the effects of nonlocal correlations and typical environment beyond the local Blackman, Esterling, and Berk (BEB) method. %coherent potential approximation. Our formalism allows us to systematically study the effects of off-diagonal disorder on the phase diagram of traditional three dimensional Anderson model. Disorder which is inevitably present in most real materials can drammatically affect their properties~\cite{Lee_RevModPhys,Belitz_RevModPhys}. It can lead to changes of their structure and transport. One of the most prominent effects of disorder is the spacial confinement of charge carriers known as Anderson localization ~\cite{Anderson}. The simplest model used to study these disorder effects is the Anderson model which is a single band tight binding model with a random on-site disorder potential. Such a model is justified when the introduction of disorder in, for example a binary alloy by substitution of host atoms by impurities, does not affect the neighbors and leads to the change of the local potential on the substitution site only. In this situation the disorder appears only in the diagonal terms of the Hamiltonian and hence is referred to as diagonal disorder (DD) case. However, in the case when the bandwidth of from the dopant impurity atoms is very different from the band width of