Electronic stopping power in insulators from first principles

TL;DR

This study uses first-principles time-dependent density-functional theory to accurately calculate electronic stopping power in insulators, revealing a threshold velocity and local energy transfer mechanisms consistent with experiments.

Contribution

It provides the first-principles calculation of electronic stopping power in insulators, demonstrating a threshold velocity and detailed energy transfer mechanisms.

Findings

Threshold velocity of ~0.2 a.u. for proton stopping power.

Proton/antiproton stopping-power ratio of ~2.4.

Energy loss is stationary and highly localized.

Abstract

Using time-dependent density-functional theory we calculate from first principles the rate of energy transfer from a moving proton or antiproton to the electrons of an insulating material, LiF. The behavior of the electronic stopping power versus projectile velocity displays an effective threshold velocity of ~0.2 a.u. for the proton, consistent with recent experimental observations, and also for the antiproton. The calculated proton/antiproton stopping-power ratio is ~2.4 at velocities slightly above the threshold (v~0.4 a.u.), as compared to the experimental value of 2.1. The projectile energy loss mechanism is observed to be stationary and extremely local.