Distortion energy distributions in the random network model of amorphous silicon

Abstract

Distortion energy distributions (DEDs) in the relaxed Polk-Boudreaux 519-atom continuous random network model (PB model) of amorphous silicon (a-Si) have been obtained. The Keating potential was used for the relaxation and calculation of the DEDs. It is found that the bond stretching DEDs over bonds and atoms fit f 1( χ 2) and f 4( χ 2) type functions, which are the chi-square distribution functions with 1 and 4 degrees of freedom, respectively. The bond bending DEDs over angles and atoms fit f 1( χ 2) and f 5( χ 2 type functions, respectively. The fact that both the bond stretching and the bond bending DEDs fit chi-square distribution functions confirms the true randomness of the relaxed PB model. The mean value of the bond bending distortion energy of an atom is found to account for the major part of the observed heat of crystallization per atom.