Ab-initio calculations for electronic structure and momentum densities of samarium sesquioxide

Abstract

We report energy bands, partial and total density of states (DOS), Mulliken’s population (MP) analysis and Compton profiles (CPs) of monoclinic and cubic Sm2O3 using linear combination of atomic orbitals scheme within local density and generalized gradient approximations (LDA and GGA). To compare the first ever theoretical momentum densities, we have measured for the first time the CP of cubic Sm2O3 using 20Ci 137Cs Compton spectrometer at an intermediate resolution of 0.34a.u. The GGA calculations with Wu–Cohen exchange and Perdew–Burke–Ernzerhof correlation functionals give a better agreement with the experimental CP than different combinations of exchange and correlation potentials within density functional theory. The energy bands along with total DOS show a wide band gap behavior in both the phases. Further in case of monoclinic phase the MP data show unequal transfer of electrons from Sm to O sites, which are in contrast to cubic phase. Such a trend of MP data is also interpreted in terms of projected DOS of Sm2O3.