A first principles characterization of electronic and optical anisotropy of quasi-one-dimensional transition metal lead sulfides PbMS3 (M [formula omitted] Hf, Zr)

Abstract

PbMS3 (M = Hf, Zr) are ternary sulfides with the general structure ABX3, where A is a metal, B is a transition metal and X is a chalcogen or halogen element. This work investigates the anisotropy of the optical and electronic properties of PbMS3, and their applicability in optoelectronic devices using first principles DFT calculations. PbHfS3 is an indirect bandgap semiconductor (1.2 eV), whereas PbZrS3 has direct bandgap (1.1 eV). The effective masses of electrons and holes exhibit strong anisotropy along the various high symmetry directions of the Brillouin zone. Important optical parameters are found to be strongly dependent on the direction of the incident radiation, best indicated by the large birefringence value. Considerable optical anisotropy suggests their promising linear and nonlinear optoelectronic applications such as polarizers, wave plates, and phase-matching elements. Small carrier effective masses, large charge recombination rates and suitable bandgap indicate the possibility of solar and photovoltaic applications.