Exploration of novel High-Pressure Structures of Hf2O3

Abstract

In the high-speed development of information technology, hafnium oxides are the most prospective alternative material for the resistive random-access memory, field-effect transistors and complementary metal oxide semiconductor transistors. Here, we carry out a systematic study on the phase transition, stability and electronic properties of Hf2O3 by using the first-principles calculations. The enthalpy pressure relations show that the P-4m2 phase has the lowest ground state energy under ambient condition, which is correspond well with the reported literatures. With the increasing pressure, at 186.1 GPa, the P-4m2 phase transforms to C2∕c phase. The calculated phonons and elastic constants of P-4m2 and C2∕c phases suggest that they are both dynamically and elastically stable. The energy band structure and the density of state calculations show that the P-4m2 phase acts as semimetal, while the C2∕c phase acts as metallic. The hardness of the P-4m2 phase and C2∕c phase have been computed based on the semiempirical method. The results indicate that P-4m2 and C2∕c phases are both hard materials with hardness values of 10.16 GPa and 19.81 GPa, respectively. We expect that our results will promote future experimental studies on Hf2O3.