Electronic stopping and proton dynamics in InP, GaP, and In$_{0.5}$Ga$_{0.5}$P from first principles

TL;DR

This study uses first-principles simulations to analyze how protons lose energy in InP, GaP, and ordered InGaP, revealing how atomic ordering influences radiation damage resistance in these semiconductors.

Contribution

It provides the first detailed real-time density functional theory analysis of electronic stopping in these materials, highlighting the role of atomic ordering and channel dependence.

Findings

Stopping varies with atomic ordering in InGaP.

Proton energy loss depends on the channeling trajectory.

Electronic stopping can be enhanced or suppressed by electron density distribution.

Abstract

The phosphide-based III-V semiconductors InP, GaP, and In$_{0.5}$Ga$_{0.5}$P are promising materials for solar panels in outer space and radioisotope batteries, for which lifetime is a major issue. In order to understand high radiation tolerance of these materials and improve it further, it is necessary to describe the early stages of radiation damage on fast time and short length scales. In particular, the influence of atomic ordering, as observed e.g. in In$_{0.5}$Ga$_{0.5}$P, on electronic stopping is unknown.We use real-time time-dependent density functional theory and the adiabatic local density approximation to simulate electronic stopping of protons in InP, GaP, and the CuAu-I ordered phase of In$_{0.5}$Ga$_{0.5}$P across a large kinetic energy range.These results are compared to SRIM and we investigate the dependence on the channel of the projectile through the target.We show that stopping can be enhanced or reduced in In$_{0.5}$Ga$_{0.5}$P and explain this using the electron-density distribution. By comparing Ehrenfest and Born-Oppenheimer molecular dynamics, we illustrate the intricate dynamics of a proton on a channeling trajectory.