Liquidlike atomic environments act as plasticity carriers in amorphous silicon

Molecular-dynamics simulation of amorphous silicon (a-Si) using the Stillinger-Weber potential reveals the existence of two distinct atomic environments: one solidlike and the other liquidlike. The mechanical behavior of a-Si when plastically deformed to large strain can be completely described by the mass fraction phi of liquidlike material in it. Specifically, samples with higher phi are more amenable to plastic flow, indicating that liquidlike atomic environments act as plasticity carriers in a-Si. When deformed under externally applied constant pressure, all a-Si samples converge to a unique value of phi characteristic of steady-state flow.