Phase Transitions and Phase Diagram of Silicon Carbide at Exoplanetary Core Conditions

Recent astrophysical observations have indicated a potential existence of carbide-rich exoplanet. This project that aims to understand the high pressure, high temperature behavior of silicon carbide (SiC) and obtain key geophysical data for the development of interior models for carbon-rich exoplanets. We combine predictive molecular dynamics simulations with experiments at the Z pulsed-power and STAR gas gun facilities to investigate the mechanisms of solid-solid and solid-liquid phase transitions in SiC. The goals of the project include delivering accurate equations of state for the solid and liquid phases of SiC, determining the melting lines of SiC phases, exploring the possibility of incongruent melting, and uncovering the effect of significant volume collapse on the kinetics of the ambient B3 to high-pressure B1 phase transition. The research is performed in collaboration with Sandia National Laboratories (SNL) and is supported by the Z Fundamental Science program and computational and experimental campaigns at DOE’s Frontier and Aurora exascale supercomputers, as well as the Z pulsed power and STAR gas gun facilities at SNL.