Dimensional crossover of collective modes in layered superionic conductors

Abstract

Using the continuum model, we have studied the dimensional crossover property of longitudinal collective modes in a layered superionic conductor (LSIC) which is composed of alternating layers of superionic conductor (SIC) and ionic crystal. The ionic plasma mode of the LSIC has changed from the three-dimensional to the two-dimensional plasma mode with increasing distance between SIC layers. As a result of this dimensional crossover of the plasma mode, the collective modes have shown various dispersion relations: the coupled optical phonon-plasma mode, the damped optical phonon mode, the relaxation mode, the diffusion mode and the acoustic phonon mode.