Ab initio calculations of pressure-dependence of high-order elastic constants using finite deformations approach

Abstract We present a description of a technique for ab initio calculations of the pressure dependence of second- and third-order elastic constants. The technique is based on an evaluation of the corresponding Lagrangian stress tensor derivative of the total energy assuming finite size of the deformations. Important details and parameters of the calculations are highlighted. Considering body-centered cubic Mo as a model system, we demonstrate that the technique is highly customizable and can be used to investigate non-linear elastic properties under high-pressure conditions.