Full diagonal disorder in a strongly correlated system

We study the electronic properties of strongly correlated materials including a full diagonal disorder for site energies εA≠εBεA≠εB as well as for correlation strengths UA≠UBUA≠UB. Correlations are treated by the dynamical mean field theory with the non-crossing approximation as impurity solver and disorder is handled by the coherent potential approximation. For half-filled systems, various metal–insulator transitions are described by spectral analysis and a phase diagram is obtained. It shows two transitions from a band insulator to a metallic state and further to a Mott–Hubbard insulator by increasing the correlation strength of only one of the constituents. Simple and double occupancies are computed for each type of site. For the doped situation, we investigate the influence of disorder restricted to the correlation strengths (εA=εBεA=εB, UA≠UBUA≠UB). We found that the site specific transfer of spectral weight is accompanied by dramatic changes of double occupancies when the metal–insulator transition occurs. Our approach gives a clear interpretation on the nature of the different bands composing the density of states and therefore on the nature of the insulating states.