Structure investigations, atomic potentials, and phase transitions of the fast ionic conductor Ag3SI

Abstract

The crystal structures and the phase transitions of α-, β-, γ-Ag3SI were investigated by single crystal X-ray diffraction in the temperature range 135 K–573 K. Anharmonic temperature factors were applied in the structure refinements. Their coefficients were used for the calculation of the probability density maps and Ag atomic potentials. Activation energies were estimated from the potentials. In the high temperature α-phase the Ag ions are distributed along crosslike bands in the (100) faces. In the β-phase they are located around the face centers. In the low temperature γ-phase the Ag ions order and a single crystal changes to a multiple domain crystal.