A high-efficient strain-stress method for calculating higher-order elastic constants from first-principles

Unexpected low thermal expansion coefficients of pentadiamond

“…Recently, by selecting proper strain modes, we proposed an efficient strain-stress method to calculate the higher-order elastic constants. 33 In this method, for a given strain mode, only the strain amplitude (Z) changes, and then eqn (2) can be written as eqn (3). The procedure of calculating elastic constants can be described as follows: (1) choosing a series of strain modes according to symmetry and applying them to the crystal.…”