First-principles elastic and mechanical properties from Born perturbation expansion

Mechanical and elastic properties of materials are among the most fundamental quantities for many engineering and industrial applications. Here, we present an efficient and accurate approach for calculating the elastic tensor of crystalline solids based on interatomic force constants and Born perturbation expansion, applicable for any dimension [1]. We have implemented the theory in the first-principles Quantum ESPRESSO distribution [2] and performed an extensive validation against conventional finite-difference calculations and experimental measurements for Si, NaCl, graphene and monolayer MoS₂. We then apply our computational approach to the high-throughput screening of elastic properties of two-dimensional materials from the MC2D database [3], and we identify various candidates with outstanding or unique mechanical properties. The methodology developed and the elastic properties computed in this work will benefit the discovery and design of novel functional materials.