Nature of insulating state in NaV2O5 above charge-ordering transition: A cluster dynamical mean-field study

The nature of the insulating state driven by electronic correlations in the quarter-filled ladder compound α'NaV 2 O 5 is investigated within a cluster dynamical mean-field approach. An extended Hubbard model with first-principles tight-binding parameters has been used. It is shown that the insulating state in the charge-disordered phase of this compound is formed due to the transfer of spectral density and dynamical charge fluctuations where for the latter, the role of intersite Coulomb interaction is found to be of crucial importance.