Glassy Quasithermal Distribution of Local Geometries and Defects in Quenched Amorphous Silicon

Simulations of amorphous silicon formed by quenching of the liquid indicate that a-Si has a Boltzmann-like distribution of local geometries, corresponding to a "glass temperature" of roughly 700 K. The resulting tetrahedral network exhibits native defects, threefold- and fivefold-coordinated atoms, which have mean formation energies of 0.6 and 0.3 eV, respectively, and which are apparently mobile even at fairly low temperatures. These results are obtained by a novel approach to the analysis, and are relatively insensitive to the empirical interatomic potential used in the simulations.