Incorporating non-adiabatic effects in Embedded Atom potentials for radiation damage cascade simulations

TL;DR

This paper develops a correction scheme for embedded atom potentials to incorporate non-adiabatic effects like electronic stopping and thermal conduction, improving radiation damage cascade simulations involving high-temperature ion-electron out-of-equilibrium conditions.

Contribution

It introduces a second-moment approximation-based correction scheme for empirical potentials to model non-adiabatic effects in radiation damage simulations.

Findings

Corrected potentials enable more accurate cascade modeling.

Applicable to bcc transition metals above Debye temperature.

Compatible with various empirical potentials.

Abstract

In radiation damage cascade displacement spikes ions and electrons can reach very high temperatures and be out of thermal equilibrium. Correct modelling of cascades with molecular dynamics should allow for the non-adiabatic exchange of energy between ions and electrons using a consistent model for the electronic stopping, electronic temperature rise, and thermal conduction by the electrons. We present a scheme for correcting embedded atom potentials for these non-adiabatic properties at the level of the second-moment approximation, and parameterize for the bcc transition metals above the Debye temperature. We use here the Finnis-Sinclair and Derlet-Nguyen-Manh-Dudarev potentials as models for the bonding, but the corrections derived from them can be applied to any suitable empirical potential.