A promising optoelectronic and thermoelectric response of full Heusler Na2TlX (X = Bi, Sb) alloys: a DFT approach

The energy conversion efficiency is one of the attributes that make Heusler alloys an extraordinary candidate for thermoelectric applications. In this paper, we have examined the electronic structure, elastic, optical and transport characteristics of full Heusler Na2TlX (X = Bi, Sb) alloys using DFT. The electronic properties are analyzed by utilizing modified Becke Johnson (mBJ) potential. The negative formation energies and optimization results reveal the stable phases of both alloys. The electronic properties exposed the semiconductor nature of both alloys. The elastic stability is obtained from various elastic parameters. The optical response of these alloys has been studied in depth by evaluating the real and imaginary dielectric functions, optical loss, refractive index and absorption coefficient. Furthermore, the thermoelectric properties are computed, which demonstrate the high electrical conductivity, Seebeck and ZT values for both alloys. The above computed attributes favor the use of studied alloys in green energy and optoelectronic applications.