Quantum many-body effects in defective transition-metal-oxide superlattices
J. A. Santana, R. Mishra, J. T. Krogel, A. Y. Borisevich, P. R. C. Kent, S. T. Pantelides, F. A. Reboredo. J. Chem. Theory Comput. (2017)
Strong electronic correlations, interfaces, defects and disorder each individually challenge theoretical methods for predictions of materials properties. These challenges are all simultaneously present in complex transition metal-oxide interfaces and superlattices, which are known to exhibit unique and unusual properties caused by multiple coupled degrees of freedom and strong electronic correlations. Here we show that ab initio quantum Monte-Carlo (QMC) solutions of the many-electron problem are now possible for the full complexity of these systems. Within a single non-empirical theoretical approach, we unambiguously establish the site-specific stability of oxygen vacancies in the (LaFeO3)2/(SrFeO3) superlattice, accounting for experimental data, and predict their migration pathways. QMC calculations are now capable of playing a major role in the elucidation of many-body phenomena in complex oxides previously out of reach of first-principles theories.