Ab Initio and Experimental Study of Vibrational Properties of TlFeS 2 and TlFeSe 2 Crystals

Vibrational properties of TlFeS 2 and TlFeSe 2 crystal lattices have been investigated experimentally using Raman scattering (RS) and infrared reflection (IR) of light, as well as theoretically, using density functional theory (DFT). Full vibrational representation, compiled on the basis of the analysis of factor symmetry groups, contains 12 RS active modes and 9 IR active modes. Of these, six active RS modes and three IR active modes have been experimentally detected and identified for TlFeS 2 , as well as four RS active modes and three IR active modes for TlFeSe 2 .