Effect of pressure on the geometric, electronic structure, elastic, and optical properties of the normal spinel MgFe2O4: a first-principles study

Abstract

Abstract First-principles computation was used to study the effect of pressure on the elastic properties, magnetic properties, optical properties, and electronic structure of the normal spinel magnesium ferrite (MgFe2O4) at different pressures (0, 10, 20, 50, 70, and 100 GPa). The normal spinel MgFe2O4 has a direct bandgap of 1.62 eV which significantly decreased to 0.42 eV with increasing the pressure to 100 GPa. The values of the elastic constants were coherent with the mechanical stability norms for cubic crystals, which revealed that MgFe2O4 was mechanically stable. The values of Pugh’s ratio indicate that MgFe2O4 is ductile at all pressure values except at 100 Gpa MgFe2O4 shows brittle behavior. The computed values of the Zener anisotropy factor at different pressures were not equal to 1.0, which indicates that MgFe2O4 is elastically anisotropic. The optical properties (refractive index, reflectivity, dielectric function, optical conductivity, and loss function) for the normal spinel MgFe2O4, as well as its magnetic moment, were calculated and discussed at different pressures.