High pressure-temperature phase diagram of silicon carbide from quantum molecular dynamics

High pressure-temperature behavior of SiC is being actively investigated with the goal of delivering key data for developing interior models of carbon-rich exoplanets. Recent experimental static  and dynamic compression studies of phase transformations in SiC have uncovered substantial differences between static and dynamic transition pressures of solid-solid phase transition from the ambient pressure zinc-blende or hexagonal to high pressure rocksalt phases. The solid-liquid melting phase transformations in SiC are also poorly understood. Quantum molecular dynamics (QMD) simulations of the SiC phase diagram and shock Hugoniots are performed within a broad range of pressures (up to 1 TPa) and temperatures (up to 50,000 K). The QMD results allow to reconcile the puzzling difference between the static and dynamic shock compression experiments while delivering accurate equation of state of the solid and liquid phases as well as the SiC melting lines.