An ab-initio DFT+DMFT study of the effect of oxygen vacancies on structural, electronic and magnetic properties of rare-earth nickelate perovskites (RNiO₃)

The electronic correlations in materials are responsible for a variety of fascinating phenomena including magnetism, superconductivity, colossal magnetoresistance and metal-insulator transitions. As shown in previous studies, the ability to manipulate the oxygen vacancies within these strongly correlated materials gives rise to new degrees of freedom in tuning their properties. We employ ab-initio density functional theory (DFT) coupled to dynamical mean field theory (DMFT) calculations to systematically study the influence of oxygen vacancies on structural, electronic and magnetic properties of strongly correlated rare-earth nickelates, RNiO₃ (R-rare earth element). The DFT Kohn-Sham orbitals are projected onto maximally localized Wannier Functions within a hybridization window to provide the correlated subspace for the DMFT problem which is solved using a continuous time quantum Monte-Carlo (CTQMC) algorithm. Based on our calculated results we elucidate the role of oxygen vacancies on the material properties also focusing their effects on individual orbitals, which thus far has not been studied extensively in the case of strongly correlated rare earth nickelate perovskites.