Incipient phase separation in Ag/Ge/Se glasses: Clustering of Ag atoms

Structural and dynamical properties of three-component chalcogenide glasses, Ag/Ge/Se, are studied using the molecular dynamics (MD) method. Effective potentials for GeSe2 and Ag2Se, which have already been well characterized, are combined to describe the interatomic interactions in the ternary system. The MD results for bond lengths, the static structure factor, and the vibrational density of states are in good agreement with neutron-scattering results. Our results elucidate the role played by silver ions as network modifiers in glass-forming GeSe2 with the medium-range correlations. Upon cooling we observe clustering of Ag atoms which indicates a tendency toward phase separation.