Dynamic Fracture in Single Crystal Silicon

TL;DR

This study compares experimental measurements of crack velocity in single crystal silicon with molecular dynamics simulations, revealing discrepancies that highlight gaps in understanding interatomic potentials.

Contribution

It provides the first direct experimental test of molecular dynamics simulations of brittle crack propagation in silicon, exposing limitations in current interatomic potentials.

Findings

Experiments and simulations disagree on crack velocities.

Current interatomic potentials do not accurately predict atomic-scale fracture behavior.

The study highlights the need for improved interatomic potentials for silicon.

Abstract

We have measured the velocity of a running crack in brittle single crystal silicon as a function of energy flow to the crack tip. The experiments are designed to permit direct comparison with molecular dynamics simulations; therefore the experiments provide an indirect but sensitive test of interatomic potentials. Performing molecular dynamics simulations of brittle crack motion at the atomic scale we find that experiments and simulations disagree showing that interatomic potentials are not yet well understood.