First-principles calculation of semiclassical thermoelectric properties of (AgSbSe₂)_n(AgSbTe₂)_n superlattices

In this research, we perform density functional – pseudo potential calculation within generalized gradient approximation (GGA) to investigate semiclassical thermoelectric properties of (AgSbSe₂)_n(AgSbTe₂)_n (n = 1,2) thin film superlattices. It is seen that GGA, GGA + U, and the modified Becke Johnson (mBJ) functionals as well as full-relativistic corrections are not able to describe properly the electronic structure of bulk AgSbSe₂ and AgSbTe₂, hence a scissor correction is used throughout this study. The Seebeck coefficient, electrical conductivity, and electronic part of the thermal conductivity of bulk compounds as well as superlattices are computed at different values of hole doping, in the fixed relaxation time approximation. It is argued that the (AgSbSe₂)₁(AgSbTe₂)₁ superlattice may exhibits improved Seebeck coefficient compared with the bulk compounds and (AgSbSe₂)₂(AgSbTe₂)₂ superlattice. - Highlights: • Ab initio study of (AgSbTe2)/(AgSbSe2) superlattice as a new thermoelectric system. • Computing Seebeck coefficient and power factor in relaxation time approximation. • Stable structure of the superlattices is determined. • Thermoelectric parameters of the superlattices are compared with the bulk materials.