Electronic correlations in early transition metal oxides with oxygen vacancies

Oxygen vacancies are known to affect profoundly the properties of the host system, coupling to the already coupled degrees of freedom. Electronically, in early transition metal oxides, the presence of oxygen vacancies locates electronic states in the gap between the transition metal t_2g-band and the oxygen p-band, with occasional occurrences of crossings with the t_2g-band. The closeness and influence of the vacancy band on the correlated electronic bands calls for a beyond-DFT analysis. Constructing an extended t_2g correlated subspace where the oxygen vacancy state is explicitly consider, we have performed dynamical mean-field theory (DMFT) and constrained random phase approximation (cRPA) calculations for three different lanthanum transition metal oxides with different t_2g-occupations (LaBO₃, with B={Ti(d¹), V(d²), Cr(d³)}) in order to investigate what is the effect of the vacancy on the Mott insulating phase, and to monitor how the ab-initio effective Coulomb interaction parameters change.