The structural and thermodynamic properties of CaLi2 at high pressure.

In this work, the structural, mechanical and thermodynamic properties of CaLi₂ in the pressure range of 0–72 GPa have been studied. It was found that CaLi₂ undergoes a phase transition from P 6 3 /mmc to C2/c phase at 25.37 GPa and from C2/c to P 2 1 /c phase at 55.99 GPa, which is consistent with previous experimental and partially theoretical results. Besides, at 0 GPa, the lowest enthalpy appears in both P 6 3 /mmc and Fd-3m structures, showing the coexistence of these two phases. However, P 6 3 /mmc phase is not stable when the pressure is larger than 6 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. [ABSTRACT FROM AUTHOR]