Theoretical investigation on the electronic and optical properties of BSTS compounds with SOC and TB_mBJ potentials

In this study, we report on electronic and optical properties of the bulk and primitive structure of A2B3 (A = Bi or Sb and B = Se or Te) compounds using FP-LAPW method within density functional theory. The potentials for exchange and correlation is treated within generalized gradient approximation-Perdew Burke Ernzerhof and Tran-Blaha modified Becke–Johnson (TB_mBJ). The inclusion of spin-orbit coupling approximation is used to calculate electronic structures and optical properties by determining the complex dielectric function, from which the other parameters are derived. The obtained results are in good agreement with the experimental results. Also, Sb2Te3 compounds have been found to possess maximum value of absorption and reflection among all the studied compounds. For all the compounds, a strong absorption coefficient (α) exists between the energy range 0 and 5 eV, and is greater than 105 cm–1, which makes them suitable for optoelectronic applications.