Multiple structural phase transitions in single crystal silicon subjected to dynamic loading

Abstract

Single crystal Silicon (SC Si), as one of the most extensively used elements, has a series of complex phase changes, however, it is not fully understood under dynamic loading conditions. In this letter, both the shock induced multiple solid-solid phase transformations and solid-liquid transition are systematically investigated using large-scale molecular dynamics (MD) simulations. With the increase of particle velocities up to 2.8 km/s, the SC Si is revealed to undergo a continuous structural phase transitions from cubic diamond (cd) to β-tin, bct5, near-simple cubic (sc), and body centered cubic (bcc) structure. Furthermore, the liquid Si is distinguished and shows solid-liquid coexistence under intensive shocks. Our work dissects the continues multiple phase transitions in shocked Si for the first time in MD simulations, which provides new understandings of phase transitions of Si under dynamic loadings, and strongly supports and complements the relevant reported experimental researches.