Incongruent Melting and Phase Diagram of SiC from Machine Learning Molecular Dynamics (Part I)

Silicon Carbide Machine Learning Molecular Dynamics Dataset (Part I)

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.

This dataset provides:

Large-scale (512K atoms) cooling MLMD trajectories

Medium-scale (8K atoms) cooling and heating MLMD trajectories

Two-phase (16K atoms) MLMD trajectories

ML force fields training data and uncertainty estimations

Please refer to README.md for more dataset information. Additional MLMD trajectories with defects are available in https://doi.org/10.5281/zenodo.15066528.