Comparison and Assessment of Different Interatomic Potentials for Simulation of Silicon Carbide

Abstract

Interatomic potentials play a crucial role in the molecular dynamics (MD) simulation of silicon carbide (SiC). However, the ability of interatomic potentials to accurately describe certain physical properties of SiC has yet to be confirmed, particularly for hexagonal SiC. In this study, the mechanical, thermal, and defect properties of four SiC structures (3C-, 2H-, 4H-, and 6H-SiC) have been calculated with multiple interatomic potentials using the MD method, and then compared with the results obtained from density functional theory and experiments to assess the descriptive capabilities of these interatomic potentials. The results indicate that the T05 potential is suitable for describing the elastic constant and modulus of SiC. Thermal calculations show that the Vashishta, environment-dependent interatomic potential (EDIP), and modified embedded atom method (MEAM) potentials effectively describe the vibrational properties of SiC, and the T90 potential provides a better description of the thermal conductivity of SiC. The EDIP potential has a significant advantage in describing point defect formation energy in hexagonal SiC, and the GW potential is suitable for describing vacancy migration in hexagonal SiC. Furthermore, the T90 and T94 potentials can effectively predict the surface energies of the three low-index surfaces of 3C-SiC, and the Vashishta potential exhibits excellent capabilities in describing stacking fault properties in SiC. This work will be helpful for selecting a potential for SiC simulations.

A Genetic Algorithm Trained Machine-Learned Interatomic Potential for the Silicon–Carbon System

“…Moreover, the Vashishta potential was not formulated to capture the physics of same atom (Si–Si or C–C) interactions . This limitation is detrimental when evaluating nonequimolar stoichiometries, which may arise during simulations involving defects, as well as during SiC peritectic decomposition, where a peritectic reaction involving silicon sublimation is reported. − …”

“…Moreover, the Vashishta potential was not formulated to capture the physics of same atom (Si−Si or C− C) interactions. 58 This limitation is detrimental when evaluating nonequimolar stoichiometries, which may arise during simulations involving defects, 59 as well as during SiC peritectic decomposition, where a peritectic reaction involving silicon sublimation is reported. 60−63 The objective of this work is to develop a new interatomic potential for the Si−C system, using a machine learning method, that narrows the gap between ab initio accuracy and classical molecular dynamics (MD) efficiency.…”