High energy γ-rays inelastic scattering studies and DFT strategies of divalent high-Z perovskites EuTMO3 (TM = Ti and Zr)

Abstract

Electron momentum densities (EMDs) of divalent high-Z perovskites EuTiO3 and EuZrO3 have been measured using 20 Ci 137Cs Compton spectrometer at 0.34 a.u. (momentum resolution). Theoretical directional and isotropic Compton profiles (CPs) for both the perovskites have been deduced using linear combination of atomic orbitals (LCAO) scheme with density functional theory (DFT). The DFT approximation dependent local density and generalized gradient approximations (GGA) along with second order GGA (SOGGA) and hybrid WC1LYP are considered in the present work. While validating the approximation for exchange and correlation energies using experimental CPs, the WC1LYP scheme has been identified as a better prescription for both the perovskites. To scrutinize the nature of bonding, we have calculated the Mulliken's populations (MP) and also scaled the experimental EMDs on equal-valence-electron-density, which explicitly show that EuTiO3 is more ionic than the EuZrO3. Going beyond the CPs, the electronic properties like energy bands and density of states (DOS) have also been enumerated using full potential linearized augmented plane wave (FP-LAPW) with GGA and GGA+Hubbard correction (U). Both the compounds show semiconducting behaviour with FP-LAPW-GGA+U scheme.