Theoretical predictions for low-temperature phases, softening of phonons and elastic stiffnesses, and electronic properties of sodium peroxide under high pressure.

ABSTRACT: High-pressure phase stabilities up to 600 K and the related properties of Na₂O₂ under pressures up to 300 GPa were investigated using first-principles calculations and the quasi-harmonic approximation. Two high-pressure phases of Na₂O₂ that are thermodynamically and dynamically stable were predicted consisting of the Amm2 (distorted P6̄2m) and the P2₁/c structures, which are stable at low temperature in the pressure range of 0-22 GPa and 22-28 GPa, respectively. However, the P6̄2m and Pbam structures become the most stable instead of the Amm2 and P2₁/c structures at the elevated temperatures, respectively. Interestingly, the softening of some phonon

SUBMITTER: Jimlim P 

PROVIDER: S-EPMC9072567 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature