Electronic effects in high-energy radiation damage in iron

TL;DR

This study uses coupled two-temperature molecular dynamics simulations to investigate electronic effects on high-energy radiation damage in iron, revealing their influence on damage production and relaxation.

Contribution

It introduces a 2T-MD model that incorporates electronic stopping and electron-ion interactions, providing new insights into radiation damage processes in iron.

Findings

2T-MD reduces damage during thermal spikes

Faster damage relaxation observed with 2T-MD

Final damage levels are similar with and without electronic effects

Abstract

Electronic effects are believed to be important in high--energy radiation damage processes where high electronic temperature is expected, yet their effects are not currently understood. Here, we perform molecular dynamics simulations of high-energy collision cascades in $\alpha$-iron using the coupled two-temperature molecular dynamics (2T-MD) model that incorporates both effects of electronic stopping and electron-ion interaction. We subsequently compare it with the model employing the electronic stopping only, and find several interesting novel insights. The 2T-MD results in both decreased damage production in the thermal spike and faster relaxation of the damage at short times. Notably, the 2T-MD model gives a similar amount of the final damage at longer times, which we interpret to be the result of two competing effects: smaller amount of short-time damage and shorter time available for damage recovery.