Calculation of elastic constants of embedded-atom-model potentials in the NVT ensamble

TL;DR

This paper presents a robust and efficient molecular dynamics method for calculating elastic constants using embedded-atom-model potentials in the NVT ensemble, applicable to non-homogeneous materials and potential calibration.

Contribution

It introduces a single-simulation approach for elastic constants in NVT MD with EAM potentials, improving speed and accuracy over traditional deformation methods.

Findings

Method yields elastic tensor with few time steps and particles.

Results agree with target values for copper across 0-1000K.

Analyzes temperature dependence of elastic contributions.

Abstract

A method for the calculation of elastic constants in the NVT ensamble, using molecular dynamics (MD) simulation with a realistic many-body embedded-atom-model (EAM) potential, is studied in detail. It is shown that in such NVT MD simulations, the evaluation of elastic constants is robust and accurate, as it gives the elastic tensor in a single simulation which converges using a small number of time steps and particles. These results highlight the applicability of this method in: (i) the calculation of local elastic constants of non-homogeneous crystalline materials and (ii) in the calibration of interatomic potentials, as a fast and accurate alternative to the common method of explicit deformation, which requires a set of consistent simulations at different conditions. The method is demonstrated for the calculation of the elastic constants of copper in the temperature range of 0-1000K, and results agree with the target values used for the potential calibration. The various contributions to the values of the elastic constants, namely, the Born, stress fluctuation and ideal gas terms, are studied as a function of temperature.