Structural and dynamical properties of liquid Si. An orbital-free molecular dynamics study

TL;DR

This study uses orbital-free ab-initio molecular dynamics to analyze static and dynamic properties of liquid silicon near melting, showing good agreement with experimental data and revealing insights into its collective excitations and transport properties.

Contribution

It provides a comprehensive orbital-free simulation of liquid silicon's properties, highlighting its similarities and differences with simple liquid metals.

Findings

Static structure matches diffraction data

Density excitations follow experimental dispersion relations

Liquid silicon cannot sustain shear wave propagation

Abstract

Several static and dynamic properties of liquid silicon near melting have been determined from an orbital free {\em ab-initio} molecular dynamics simulation. The calculated static structure is in good agreement with the available X-ray and neutron diffraction data. The dynamical structure shows collective density excitations with an associated dispersion relation which closely follows recent experimental data. It is found that liquid silicon can not sustain the propagation of shear waves which can be related to the power spectrum of the velocity autocorrelation function. Accurate estimates have also been obtained for several transport coefficients. The overall picture is that the dynamic properties have many characteristics of the simple liquid metals although some conspicuous differences have been found.