The structural and thermodynamic properties of CaLi2 at high pressure

Abstract

In this work, the structural, mechanical and thermodynamic properties of CaLi2 in the pressure range of 0–72[Formula: see text]GPa have been studied. It was found that CaLi2 undergoes a phase transition from P[Formula: see text]/mmc to C2/c phase at 25.37[Formula: see text]GPa and from C2/c to P[Formula: see text]/c phase at 55.99[Formula: see text]GPa, which is consistent with previous experimental and partially theoretical results. Besides, at 0[Formula: see text]GPa, the lowest enthalpy appears in both P[Formula: see text]/mmc and Fd-3m structures, showing the coexistence of these two phases. However, P[Formula: see text]/mmc phase is not stable when the pressure is larger than 6[Formula: see text]GPa. Finally, the elastic of CaLi2 at different pressures was investigated using the elastic stability criterion, and the thermodynamic properties under different pressures are investigated in detail.