Atomic topology and radial distribution functions of a-SiNx alloys: ab initio simulations

Random structures of amorphous silicon–nitrogen alloys, a-SiNx, are obtained for several values of x from 0 to the nearly stoichiometric composition of x=1.29, using a new ab initio thermal procedure based on a Harris-functional code and periodically continued cells with 64 atoms. Partial radial features are reported with no experimental counterparts for comparison, whereas the total radial distribution functions agree very well with the few existing experiments. Our average coordination numbers also agree very well with experiment. These results, being predictive, may stimulate further experimental and theoretical studies.