An atomistic study of phase transition in cubic diamond Si single crystal subjected to static compression

It is been widely experimentally reported that Si under static compression (typically in a Diamond Anvil Setup-DAC) undergoes different phase transitions. Even though numerous interatomic potentials are used for numerical studies of Si under different loading conditions, the efficacy of different available interatomic potentials in determining the phase transition behavior in a simulation environment similar to that of DAC has not been probed in literature which this manuscript addresses. Hydrostatic compression of Silicon using seven different interatomic potentials demonstrates that Tersoff(T0) performed better as compared to other potentials with regards to demonstration of phase transition. Using this Tersoff(T0) interatomic potential, molecular dynamics simulation of cubic diamond single crystal silicon has been carried out along different directions under uniaxial stress condition to determine anisotropy of the samples, if any. β-tin phase could be observed for the [0 0 1] direction loading whereas Imma along with β-tin phase could be observed for [0 1 1] and [1 1 1] direction loading. Amorphization is also observed for [0 1 1] direction. The results obtained in the study are based on rigorous X-ray diffraction analysis. No strain rate effects could be observed for the uniaxial loading conditions.