Liquid-liquid transition in supercooled silicon determined by first-principles simulation

TL;DR

This study uses first-principles simulations to identify a liquid-liquid phase transition in supercooled silicon, revealing two distinct phases with different structures and electronic properties below approximately 1232K.

Contribution

The paper provides the first direct simulation evidence of a liquid-liquid transition in supercooled silicon, characterizing the structural and electronic differences between the phases.

Findings

Two coexisting liquid phases below 1232K.

Low density phase is nearly tetra-coordinated with a pseudogap.

High density phase is more coordinated and metallic.

Abstract

First principles molecular dynamics simulations reveal a liquid-liquid phase transition in supercooled elemental silicon. Two phases coexist below $T_c\approx 1232K$. The low density phase is nearly tetra-coordinated, with a pseudogap at the Fermi surface, while the high density phase is more highly coordinated and metallic in nature. The transition is observed through the formation of van der Waals loops in pressure-volume isotherms below $T_c$.