Models and modeling schemes for binary IV-VI glasses

In this paper, we present and thoroughly characterize several new models of amorphous binary IV-VI glasses. We apply both a quench from the melt simulation regime and a scheme based on decoration of tetrahedral amorphous networks. We show that for certain binary IV-VI glasses (especially silica), decoration of bond-centered column VI atoms on tetrahedral amorphous networks leads with appropriate re-scaling and relaxation to highly realistic models of the IV-VI glass. In particular, the problem of freezing in too much liquid-like character seems to be significantly ameliorated. We also carry out first-principles molecular dynamics simulations to study the structural, dynamical, and electronic properties of GeSe4 and GeSe9. Good agreement with experiment is obtained for the total neutron structure factor over the entire range of k-space and for the electronic density of states.