Phase diagram of silicon from atomistic simulations

TL;DR

This paper presents an atomistic simulation-based phase diagram of silicon across a range of pressures and temperatures, accurately capturing phase boundaries and triple points.

Contribution

It introduces an efficient simulation approach combining tight binding models and free energy calculations to determine silicon's phase diagram.

Findings

Phase boundaries and triple points are identified.

The simulated phase diagram agrees well with experimental data.

The method accurately predicts silicon's phase behavior across conditions.

Abstract

In this letter we present a calculation of the temperature-pressure phase diagram of Si in a range of pressures covering from -5 to 20 GPa and temperatures up to the melting point. The phase boundaries and triple points between the diamond, liquid, $\beta$-Sn and ${Si}_{34}$ clathrate phases are reported. We have employed efficient simulation techniques to calculate free energies and to numerically integrate the Clausius-Clapeyron equation, combined with a tight binding model capable of an accuracy comparable to that of first-principles methods. The resulting phase diagram agrees well with the available experimental data.