Performance of hybrid functional in linear combination of atomic orbitals scheme in predicting electronic response in spinel ferrites ZnFe2O4 and CdFe2O4

Abstract

Pure and hybrid density functional theory (DFT) schemes within linear combination of atomic orbitals (LCAO) have been employed to compute Mulliken population (MP), energy bands, density of states (DOS) and electron momentum densities (EMDs) of TMFe2O4 (TM = Zn and Cd). Pure DFT calculations were performed within local density and generalized gradient approximations, while Hartree–Fock exchange contribution is added to DFT for hybrid calculations (B3LYP and PBE0). To validate the performance of hybrid functionals, we have also performed EMD measurements using 661.65 keV γ-rays from 137Cs source. Chi-square test predicts an overall better agreement of experimental Compton profile data with LCAO–B3LYP scheme-based momentum densities leading to usefulness of hybrid functionals in predicting electronic and magnetic response of such ferrites. Further, LCAO–B3LYP-based majority- and minority-spin energy bands and DOS for ZnFe2O4 and CdFe2O4 predict semiconducting nature in both the compounds. In addition, MP data and equal-valence-electron-density scaled EMDs show more covalent character of ZnFe2O4 than that of CdFe2O4. A reasonable agreement of magnetic moments of both the ferrites with available data unambiguously promotes use of Gaussian-type orbitals in LCAO scheme in exploring magnetic properties of such ferrites.