Tuning of tetrahedrality in a silicon potential yields a series of monatomic (metal-like) glassformers of very high fragility

TL;DR

This study demonstrates how tuning tetrahedrality in a silicon potential creates highly fragile monatomic glass formers, revealing insights into vitrification near the diamond-beta-tin-liquid triple point.

Contribution

The paper introduces a method to modify silicon potentials to produce monatomic glass formers with high fragility, exploring the liquid's phase behavior near triple points.

Findings

Monatomic glass formers are created by adjusting tetrahedrality.

Crystallization is preceded by polyamorphic transformations.

High fragility of the resulting glass-forming liquids.

Abstract

We obtain monatomic glass formers in simulations by modifying the tetrahedral character in a silicon potential to explore a triple point zone between potentials favoring diamond (dc) and bcc crystals. dc crystallization is always preceded by a polyamorphic transformation of the liquid, and is frustrated when the Kauzmann temperature of the high temperature liquid intersects the liquid-liquid coexistence line. The glass forming liquids are extraordinarily fragile. Our results suggest that Si and Ge liquids may be vitrified at a pressure close to the diamond-beta-tin-liquid triple point.