Incongruent Melting and Phase Diagram of SiC from Machine Learning Molecular Dynamics

Fuente: arXiv
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Main Authors: Xie, Yu, Wang, Menghang, Ramakers, Senja, Spaepen, Frans, Kozinsky, Boris
Format: Preprint
Published: 2025
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author Xie, Yu
Wang, Menghang
Ramakers, Senja
Spaepen, Frans
Kozinsky, Boris
author_facet Xie, Yu
Wang, Menghang
Ramakers, Senja
Spaepen, Frans
Kozinsky, Boris
contents Silicon carbide (SiC) is an important technological material, but its high-temperature phase diagram has remained unclear due to conflicting experimental results about congruent versus incongruent melting. Here, we employ large-scale machine learning molecular dynamics (MLMD) simulations to gain insights into SiC decomposition and phase transitions. Our approach relies on a Bayesian active learning workflow to efficiently train an accurate machine learning force field on density functional theory data. Our large-scale simulations provide direct indication that melting of SiC proceeds incongruently via decomposition into silicon-rich and carbon phases at high temperature and pressure. During cooling at high pressures, carbon nanoclusters nucleate and grow within the homogeneous molten liquid. During heating, the decomposed mixture reversibly transitions back into a homogeneous SiC liquid. The full pressure-temperature phase diagram of SiC is systematically constructed using MLMD simulations, providing new understanding of the nature of phases, resolving long-standing inconsistencies from previous experiments and yielding technologically relevant implications for processing and deposition of this material.
format Preprint
id arxiv_https___arxiv_org_abs_2502_17804
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Incongruent Melting and Phase Diagram of SiC from Machine Learning Molecular Dynamics
Xie, Yu
Wang, Menghang
Ramakers, Senja
Spaepen, Frans
Kozinsky, Boris
Materials Science
Silicon carbide (SiC) is an important technological material, but its high-temperature phase diagram has remained unclear due to conflicting experimental results about congruent versus incongruent melting. Here, we employ large-scale machine learning molecular dynamics (MLMD) simulations to gain insights into SiC decomposition and phase transitions. Our approach relies on a Bayesian active learning workflow to efficiently train an accurate machine learning force field on density functional theory data. Our large-scale simulations provide direct indication that melting of SiC proceeds incongruently via decomposition into silicon-rich and carbon phases at high temperature and pressure. During cooling at high pressures, carbon nanoclusters nucleate and grow within the homogeneous molten liquid. During heating, the decomposed mixture reversibly transitions back into a homogeneous SiC liquid. The full pressure-temperature phase diagram of SiC is systematically constructed using MLMD simulations, providing new understanding of the nature of phases, resolving long-standing inconsistencies from previous experiments and yielding technologically relevant implications for processing and deposition of this material.
title Incongruent Melting and Phase Diagram of SiC from Machine Learning Molecular Dynamics
topic Materials Science
url https://arxiv.org/abs/2502.17804