Investigation of ordered dispersive effect, charge density, thermal properties and disappearance of spin polarization in perovskite CsBeO3 under the influence of pressure-A DFT perspective

Abstract

Full Potential Linearized Augmented Plane Wave method (FP-LAPW) was employed to investigate the behavior of cubic perovskite CsBeO3 under the influence of pressure. The spin polarized study has been carried out in PBE-GGA approximation under the application of pressure. The variation of pressure is attained by the appropriate reduction of volume for the compound. At equilibrium volume and at 0 GPa, the compound CsBeO3 is found to exhibit energy gap in the spin up direction and the spin down direction is largely conducting. With the reduction of volume and their corresponding increase in pressure, the electronic behavior changes for the compound. At a pressure of about 10 GPa, the s-orbital of Cs atom undergoes energy excitation to higher energy level due to an ordered dispersive effect at s-orbital. This results in the disappearance of energy gap and the compound becomes conducting in spin up direction and the half metallic ferromagnetism is found to disappear at increased pressure. Thermal properties such as Debye temperature and Curie point have been reported in this work. Elastic constants and anisotropy factor have been determined and compared at different pressures.