Abstract:
Distortion of the density of states(DOS) via resonant level has been reported to
improve the thermoelectric figure of merit (ZT) of material. BaCu2S2 exists in two
phases a high-temperature tetragonal phase and a low-temperature orthorhombic
phase. In this study, we tried doping various elements(Al, Ga, In, Tl, As, and Sb)
at different sites of both phases. For the lowest formation energy configurations, we
further explored the effect of various dopants in the electronic structure of the compound.
Some of the dopants created new defect states overlapping with the parent
states(resonant level), close to the band edge. Tl created defect states in both the
VB and CB band edges. Studied the thermoelectric properties of dopants. Group
13 dopants in the orthorhombic phase showed a carrier concentration-dependent
improvement in Seebeck coefficients for both the holes and electrons due to the
resonant level.