Interrelationship between structural, optical and transport properties of InP1−xBix: DFT approach

In this paper, the effect of Bi concentrations on the electronic structure, optical and thermoelectric properties was studied, using the density functional theory. The form of the generalized gradient approximation (GGA) proposed by Engel and Vosko (EVGGA) are used for the exchange and correlation potential. From the partial density of states, we find out that increasing the concentration of Bi results in a decrease of band gap of the compound. The PDOS of the InP compound elucidates that the valence bands are mainly comprised of P-p states, while the conduction band is mainly formed by foremost In-s and P-p with small contribution of P-s state while in InP/InB alloys the Bi-p stated strongly contribute in valance bands along with P-p states. From the calculated electronic structure we calculated the frequency dependent dielectric function along with other related optical constant. The transport coefficients are calculated using the semiclassical Boltzmann theory, as a function of temperature assuming a constant relaxation time. The Seebeck coefficient tended to decrease with increasing Bi content, whereas at low temperature figure of merit decreases with increasing the concentration of Bi.