Thermoelectric and optical properties of the SrS graphene by DFT

Abstract

ABSTRACT The mechanical, electrical, optical and thermoelectric properties of SrS graphene-like structure are discussed using the density functional theory and FP-Lapw method. To calculate the electrical properties, the generalized gradient approximation, Kohn–Sham, and Green function Waves function approximations are used in our correlation potential, and the optical calculations are performed based on the Time-dependent density functional theory (TDDFT), Bethe-Salpeter equation, and Random Phase approximation approximations. The structural calculations suggest the phonon stability of SrS, with an observed optical phonon gap in the range of 5–9 THz, indicating that the bonds are ionic. The electronic calculations show that the SrS graphene-like has a direct bandgap of 2.6 eV and also the static value of its real dielectric function has the maximum value with RPA, and minimum value with BSE approximations. In the BSE and TDDFT approximations, the optical behaviour of SrS graphene-like shows optical stability in the infrared, visible and UV edge regions. It has an excellent thermoelectric quality at room temperature, and remarkably its thermoelectric behaviour is stable even beyond 500 K, hence it is a good choice for power generators.