Nanoscale molecular dynamics simulation of shock compression of silicon

Shock waves in solids provide a unique opportunity to study the fundamental physics and chemistry of matter at extreme pressures and temperatures. In spite of substantial theoretical and experimental efforts a full understanding of shock-induced elastic and plastic responses and polymorphic phase transitions is still far from complete. These phenomena often occur at the nanometer size and picosecond time scales which makes molecular dynamics simulations an ideal tool for exploring nanoscale mechanisms of shock induced processes such as chemical reactions and phase transitions. We report results of molecular dynamics simulation of shock wave propagation in silicon in [100], [110], and [111] directions obtained using a classical interatomic potential. Several regimes of materials response are classified as a function of shock wave intensity and crystalline orientation of shock wave propagation using calculated shock Hugoniot. The shock induced chemistry and shock wave splitting are discussed in relation to recent experimental results [1] that indicate anomalous elastic response of the lattice at high compression ratios. [1] A. Loveridge-Smith, Phys. Rev. Let. \textbf{86}, 2349 (2001).