First principles study of structural, electronic, elastic and thermodynamic properties of cubic HfO2 under pressure

摘要

In this paper, we report the results of the density functional theory (DFT)-based theoretical calculations of structural, electronic and elastic properties of HfO2 in cubic phase (c-HfO2) under pressure up to 30 GPa using full-potential linearized augmented plane wave (FP-LAPW) approach as implemented in Wien2k package. The generalized gradient approximation as parameterized by Wu-Cohen (GGA-WC) and the Tran-Blaha modified Becke-Johnson exchange potential (mBJ) with improved parameterization by Koller were used for the exchangecorrelaton effect, the later was employed with objetive of obtaining accurate band gap of the compound. Our results of structural optimization are in good agreement with other available theoretical ones and experimental datas, and we found that the volume of c-HfO2 decreases with pressure. Our electronic calculations indicate that c-HfO2 has indirect band gap X-F whose value is 6.189 eV, and this value increases with increasing pressure. The calculated elastic properties show that this material is ductile for pressures up to 12.5 GPa, and then it becomes elastically brittle. Finally, the thermodynamic properties of c-HfO2, such as, heat capacities, thermal expansion, Debye temperature, Griineisen parameter and entropy under high pressures and temperatures were computed using the quasi-harmonic Debye model as embedded in GIBBS2 code and analyzed in details.