Liquid-liquid phase transition in Stillinger-Weber silicon

TL;DR

This paper investigates how perturbations like pressure and potential modifications influence the liquid-liquid phase transition in Stillinger-Weber silicon, revealing its sensitivity to such factors and potential variability in its existence.

Contribution

It demonstrates that the liquid-liquid transition in Stillinger-Weber silicon is highly sensitive to pressure and potential parameters, affecting its order and existence.

Findings

Negative pressure changes the transition order.

Strengthening the three-body term can eliminate the transition.

The phase transition's existence depends on potential details.

Abstract

It was recently demonstrated that the Stillinger-Weber silicon undergoes a liquid-liquid first-order phase transition deep into the supercooled region (Sastry and Angell, Nature Materials 2, 739 (2003)). Here we study the effects of perturbations on this phase transition. We show that the order of the liquid-liquid transition changes with negative pressure. We also find that the liquid-liquid transition disappears when the three-body term of the potential is strengthened by as little as 5 %. This implies that the details of the potential could affect strongly the nature and even the existence of the liquid-liquid phase.