paper

Covalency and the metal-insulator transition in titanate and vanadate perovskites

arXiv:1309.2995 · doi:10.1103/PhysRevB.89.161113

Abstract

A combination of density functional and dynamical mean-field theory is applied to the perovskites SrVO, LaTiO and LaVO. We show that DFT+DMFT in conjunction with the standard fully localized-limit (FLL) double-counting predicts that LaTiO and LaVO are metals even though experimentally they are correlation-driven ("Mott") insulators. In addition, the FLL double counting implies a splitting between oxygen and transition metal levels which differs from experiment. Introducing into the theory an \textit{ad hoc} double counting correction which reproduces the experimentally measured insulating gap leads also to a - splitting consistent with experiment if the on-site interaction is chosen in a relatively narrow range ( eV). The results indicate that these early transition metal oxides will serve as critical test for the formulation of a general \textit{ab initio} theory of correlated electron metals.

5 pages, 3 figures

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