Work

Unraveling the atomic-scale pathways driving pressure-induced phase transitions in silicon

Year: 2024

Type: article

Abstract: Silicon exhibits several metastable allotropes which recently attracted attention in the quest for materials with superior (e.g. optical) properties, compatible with Si technology. In this work we shed light on the atomic-scale mechanisms leading to phase transformations in Si under pressure. To do so, we synergically exploit different state-of-the-art approaches. In particular, we use the advanced GAP interatomic potential both in NPT molecular dynamics simulations and in solid-state nudged elastic band calculations, validating our predictions with ab initio DFT calculations. We provide a link between evidence reported in experimental nanoindentation literature and simulation results. Particular attention is dedicated to the investigation of atomistic transition paths allowing for the transformation between BC8/R8 phases to the hd one under pure annealing. In this case we show a direct simulation of the local nucleation of the hexagonal phase in a BC8/R8 matrix and its corresponding atomic-scale mechanism extracted by the use of SS-NEB. We extend our study investigating the effect of pressure on the nucleation barrier, providing an argument for explaining the heterogeneous nucleation of the hd phase and unraveling its main parameters with possible applications to the design of nanostructured materials.

Source: Materials Today Nano

DOI: 10.1016/j.mtnano.2024.100548

Authors: Fabrizio Rovaris, Anna Marzegalli, Francesco Montalenti, Emilio Scalise

Institution: University of Milano-Bicocca

Language: English

Topic: High-pressure geophysics and materials

Subfield: Geophysics

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,020

Funders: European Commission, Ministero dell’Istruzione, dell’Università e della Ricerca