Constant-pressure molecular dynamics of amorphous Si

Metastable materials like amorphous silicon (a-Si) are created under non-equilibrium conditions, such as quenching from the melt. Therefore, in contrast to the equilibrium phases, careful control of the external thermodynamic variables (temperature and pressure) is important, as they influence the quality of the material produced. We present a scheme for incorporating temperature and pressure control in tight-binding molecular dynamics. It is applied to a-Si formation from the melt under zero external pressure. The influence of the control mechanisms is studied. The characteristics of the prepared a-Si specimen are discussed.