Dynamical screening effects on formation of swift heavy ions damage in GaN

TL;DR

This study employs a multiscale simulation approach combining Monte Carlo and molecular dynamics to investigate how dynamical screening influences damage formation by swift heavy ions in GaN, revealing detailed damage structures.

Contribution

It introduces a coupled simulation method that incorporates dynamical charge screening effects, providing new insights into ion track formation in GaN.

Findings

Formation of amorphous ion track cores with voids filled with nitrogen.

Damaged regions contain edge dislocations consistent with experiments.

Dynamical screening significantly affects damage morphology.

Abstract

We used a multiscale model to study the damage caused by swift heavy ions in GaN. The model combines Monte Carlo and molecular dynamics simulations to analyze the material response to the excitation initiated by a projectile. We found that the most appropriate simulation approach couples the dynamical screening of charges of target atoms during the scattering of fast electrons with the Tersoff-Brenner interatomic potential describing atomic dynamics in the excited target. The simulations demonstrate the formation of damaged ion tracks with an amorphous core, containing voids filled with nitrogen. The core is surrounded by a damaged crystalline region containing edge dislocations, consistent with experimental observations.