Elastic Constants of NaCl under Pressure via First-Principles Calculations

The elastic constants of the B1 structure NaCl under pressure are obtained by using the ab initio plane-wave pseudopotential density functional theory method. The obtained zero pressure lattice constant and elastic constants are in good agreement with the available experimental data. It is found that the elastic constants C₁₁ and C₁₂ and the bulk modulus B increase monotonically with pressure P, however C₄₄ increases monotonically when P≤28GPa and decreases when P>28GPa. Moreover, we discuss the B1-B2 structure phase transition of NaCl and obtain the transition pressure of 28.3GPa.