Nanoscale Molecular Dynamics Simulaton of Shock Compression of Silicon

TL;DR

This study uses molecular dynamics simulations to analyze shock wave propagation in silicon along different crystallographic directions, revealing distinct regimes of response and a unique anomaly in the [110] direction.

Contribution

It provides detailed simulation-based insights into the directional dependence of shock response and identifies an unusual behavior in the [110] orientation of silicon.

Findings

Shock wave structure varies with direction and velocity.

[100] and [111] directions show elastic and plastic wave evolution.

[110] direction exhibits an anomalous response without plastic deformation.

Abstract

We report results of molecular dynamics simulation of shock wave propagation in silicon in [100], [110], and [111] directions obtained using a classical environment-dependent interatomic potential (EDIP). Several regimes of materials response are classified as a function of shock wave intensity using the calculated shock Hugoniot. Shock wave structure in [100] and [111] directions exhibit usual evolution as a function of piston velocity. At piston velocities km/s the shock wave consists of a fast elastic precursor followed by a slower plastic front. At larger piston velocities the single overdriven plastic wave propagates through the crystal causing amorphitization of Si. However, the [110] shock wave exhibits an anomalous materials response at intermediate piston velocities around km/s which is characterized by the absence of plastic deformations.