Electronic Structure and Elastic Properties of Strongly Correlated Metal Oxides from First Principles: LSDA + U, SIC-LSDA and EELS Study of UO2 and NiO

Abstract

We compare experimentally observed electron energy loss spectra (EELS) of uranium dioxide UO2 and nickel monoxide NiO with the results of ab-initio calculations carried out by using a method combining the local spin density approximation and the Hubbard U term (the LSDA + U method). We show that by taking better account of strong Coulomb correlations between electrons in the 5f shell of uranium ions in UO2 and in the 3d shell of nickel ions in NiO it is possible to arrive at a better description of electron energy loss spectra, cohesive energies and elastic constants of both oxides compared with local spin density functional theory. For NiO we also compare the LSDA + U results and EELS spectra with a self-interaction corrected LSDA calculation.