Atomistic mechanisms of phase nucleation and propagation in a model two-dimensional system
Date
2022-12-07
Authors
Major Professor
Advisor
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
The Royal Society
Abstract
We present a computational study on the solid–solid phase transition of a model two-dimensional system between hexagonal and square phases under pressure. The atomistic mechanism of phase nucleation and propagation are determined using solid-state Dimer and nudged elastic band (NEB) methods. The Dimer is applied to identify the saddle configurations and NEB is applied to generate the transition minimum energy path (MEP) using the outputs of Dimer. Both the atomic and cell degrees of freedom are used in saddle search, allowing us to capture the critical nuclei with relatively small supercells. It is found that the phase nucleation in the model material is triggered by the localized shear deformation that comes from the relative shift between two adjacent atomic layers. In addition to the conventional layer-by-layer phase propagation, an interesting defect-assisted low barrier propagation path is identified in the hexagonal to square phase transition. The study demonstrates the significance of using the Dimer method in exploring unknown transition paths without a priori assumption. The results of this study also shed light on phase transition mechanisms of other solid-state and colloidal systems.
Series Number
Journal Issue
Is Version Of
Versions
Series
Academic or Administrative Unit
Type
article
Comments
This is a manuscript of an article published as Shuang, Fei, Penghao Xiao, Liming Xiong, and Wei Gao. "Atomistic mechanisms of phase nucleation and propagation in a model two-dimensional system." Proceedings of the Royal Society A 478, no. 2268 (2022): 20220388.
DOI: 10.1098/rspa.2022.0388.
Copyright 2022 The Author(s).
Posted with permission.