Phase Transition in Superionic Conductor Ag₂Se: A Molecular Dynamics Study

Abstract

A computer simulation by a constant-temperature and constant-pressure molecular dynamics method has been applied to Ag₂Se to investigate the low temperature phase transition between a superionic phase and a nonsuperionic phase. The pair-wise potential model used by Rino et al. to study the superionic and molten state of Ag₂Se has been used. The low temperature structure obtained by the calculations is orthorhombic with a=4.29, b=6.82, c=8.25 Å, and the space group is Pmnb. This is very similar to that observed experimentally, which is orthorhombic with a=4.333, b=7.062, c=7.764 Å, and the space group, P2₁2₁2₁.