Vibrational and thermoelastic properties of bcc iron from selected EAM potentials

TL;DR

This study evaluates the vibrational, thermodynamic, and thermoelastic properties of bcc iron using classical molecular dynamics with semi-empirical potentials, comparing results to experimental data to assess potential accuracy.

Contribution

It provides a critical assessment of selected EAM potentials for modeling bcc iron's thermoelastic properties through molecular dynamics simulations.

Findings

EAM potentials show limitations in accurately predicting thermoelastic properties.

Simulation results highlight discrepancies with ultrasonic measurements.

The study identifies specific potentials that better approximate experimental data.

Abstract

A comprehensive, critical study of the vibrational, thermodynamic and thermoelastic properties of bcc iron is presented, using well established semi-empirical embedded-atom method potentials available in the literature. Classical molecular dynamics simulations are used to address temperature effects, where dynamical matrices are constructed as a time average of the second moment of the atomic displacements. The $C_{11}, C_{44}, C'$ elastic constants are then obtained from the sound velocities along high symmetry directions in reciprocal space. Results are compared to ultrasonic measurements and highlight the limitations of the potentials considered here in describing thermoelastic properties.