Ellipsometric studies of (Cu6PS5I)1-x(Cu7PS6)x and (Cu6PS5Br)1-x(Cu7PS6)x mixed crystals

Abstract

(Cu6PS5I)1–x(Cu7PS6)x and (Cu6PS5Br)1–x(Cu7PS6)x mixed crystals were grown using a direct crystallization technique from the melt. Refractive indices and extinction coefficients for mixed crystals were obtained from the spectral ellipsometry measurements. A nonlinear increase of the refractive indices is revealed with increase of Cu7PS6 content. The dispersion of refractive indices is described in the framework of Wemple–DiDomenico model. The compositional dependences of optical parameters for (Cu6PS5I)1–x(Cu7PS6)x and (Cu6PS5Br)1–x(Cu7PS6)x mixed crystals are analyzed.

Keywords

• superionic conductors
• mixed crystals
• spectral ellipsometry
• refractive index
• extinction coefficient