Structure and dynamics of l-Ge: Neutron scattering experiments and ab initio molecular dynamics simulations

TL;DR

This study combines neutron scattering experiments and ab initio simulations to analyze the structure and dynamics of liquid germanium, demonstrating that atomistic models can accurately represent its properties and fluctuations.

Contribution

First combined experimental and ab initio simulation study of liquid germanium's structure and dynamics, validating the accuracy of atomistic models.

Findings

Simulations reproduce experimental scattering results.

Atomistic model accurately describes liquid germanium structure.

Data assesses simple models for diffusion in l-Ge.

Abstract

We report the first measurements of the dynamics of liquid germanium (l-Ge) by quasi-elastic neutron scattering on time-of-flight and triple-axis spectrometers. These results are compared with simulation data of the structure and dynamics of l-Ge which have been obtained with ab initio density functional theory methods. The simulations accurately reproduce previous results from elastic and inelastic scattering experiments, as well as the q-dependence of the width of the quasi-elastic signal of the new experimental data. In order to understand some special features of the structure of the liquid we have also simulated amorphous Ge. Overall we find that the atomistic model represents accurately the average structure of real l-Ge as well as the time dependent structural fluctuations. The new quasi-elastic neutron scattering data allows us to investigate to what extent simple theoretical models can be used to describe diffusion in l-Ge.