Low temperature phase transformation in superionic conductors: A molecular dynamics study of silver sulfide

摘要

Upon lowering the temperature below 450 K the superionic solid Ag2S undergoes a structural phase transformation from a bcc sulfur lattice with the space group Im3mto a monoclinic lattice with the space groupP21/c. We have successfully modeled this transformation using the variable sizendash;shape form of molecular dynamics and a pair potential constructed earlier to model structural and transport properties in the superionic phase. Very good agreement is found between the partial pair distribution functions for the transformed crystal and the distribution functions calculated using the atomic positions obtained in xhyphen;ray studies. We also find good agreement between the threehyphen;body angular distributions calculated for the transformed system and distributions calculated for the structure based on the xhyphen;ray positions.