Vibrational studies of lithium-intercalated SnS 2

Abstract

We report on the vibrational properties of lithium-intercalated SnS 2 single crystal. Raman scattering and infrared absorption spectra have been recorded as a function of temperature in the frequency range 50–600 cm −1. The new bands are interpreted such as modes due to vibrations of lithium atoms located in the van der Waals gap against the nearest neighbouring chalcogen atoms. Results are analyzed in terms of stretching vibrations of LiS 4 and LiS 6 entities. From a comparison of the spectra, it is concluded that lithium ions are more likely to occupy tetrahedral sites in the lithium-rich phase. Using a simple model of lattice dynamics, the coupling force constants are determined and compared with those of the pristine material.