Ab initio generation of amorphous semiconducting structures. The case of a-Si

Using a new thermal process and an ab initio molecular dynamics method based on the Harris functional on originally crystalline, periodically continued 64-atom diamond-like cells, we generate amorphous silicon (a-Si) with a 10.0 fs time step. We obtain radial and angular distribution functions and analyze the topology of the models. The radial distribution function (RDF) obtained shows four characteristic experimental peaks and agrees with all known experimental results reported up to date. The bond-angle and dihedral distributions are also obtained, as well as the number of n-atom rings. The structures generated have fewer bond defects than those produced from the melt.