Melting of cubic boron nitride at extreme pressures.

摘要: Due to its large pressure range of stability and inert nature, cubic boron nitride has been proposed as a potential standard for high experiments. It is extremely refractive upon compression, although melting temperature not known beyond 10 GPa. We apply first-principles molecular dynamics evaluate the thermodynamics zincblende structured (cubic) liquid at extreme temperatures pressures, compute curve up 1 TPa by integration Clapeyron equation. The resulting equations state reveal that becomes denser than solid phase pressures around 0.5 TPa. This expressed turnover in curve, which reaches maximum 510 GPa 6550 ± 700 K. origin this density crossover explained terms underlying structure, diverges from phases are compressed.