Large optical anisotropy in quasi-one-dimensional tantalum thallium chalcogenides TaTlX3 (X = S, Se): A first-principles investigation

Abstract

Anisotropy of optical parameters of TaTlS3 and TaTlSe3 is investigated through first principles calculations. Indirect bandgap quasi-one-dimensional semiconductors TaTlS3 and TaTlSe3 have bandgaps of 1.15 eV and 0.84 eV, respectively. Important optical parameters are found to be strongly influenced by the radiation direction of the incident beam, as indicated by large birefringence and dichroism. Large optical anisotropy suggests promising nonlinear and linear optoelectronic applications for these materials, including wave plates, polarizers and phase-matching devices.