Polarization-Dependent Raman Selection Rules in Sb${}_2$S${}_3$ from First Principles and Experiment

Abstract

Antimony sulfide (Sb${}_2$S${}_3$) is a semiconductor composed of quasi-one-dimensional ribbon-like structural units, which give rise to pronounced structural anisotropy in the bulk crystal. Despite growing interest in Sb${}_2$S${}_3$, in particular Sb${}_2$S${}_3$ thin films, a detailed understanding of its symmetry-based lattice dynamics remains incomplete. Here, we present a combined experimental and theoretical study of polarization-dependent Raman scattering in Sb${}_2$S${}_3$ thin films. We derive the Raman selection rules from the crystal symmetry and calculate the zone-center phonon modes and corresponding Raman tensors using density functional theory. The calculated polarization dependencies are systematically compared with polarization-dependent Raman measurements performed on oriented crystalline domains of Sb${}_2$S${}_3$ thin films. This combined analysis enables reliable mode assignments, elucidates the anisotropic Raman response associated with the ribbon-like crystal structure, and demonstrates the sensitivity of polarized Raman spectroscopy to crystal orientation and structural order in antimony chalcogenide (Sb${}_2$S${}_3$, Sb${}_2$Se${}_3$) as well as isostructural Bi${}_2$S${}_3$ thin films.

16 pages, 10 figures