Thermoelectric properties of doped topological half-Heusler LuPdBi_1-xZ_x (Z = P, As, Sb) compounds

Utilizing first-principles calculations and the Boltzmann transport equation under the constant relaxation time approximation, the electronic and thermoelectric properties of doped half-Heusler (HH) LuPdBi_0.75Z_0.25 (Z = P, As, Sb) compounds have been explored. The mechanical stability of the resulting compounds is confirmed via computed values of various elastic constants. Our findings demonstrate that the substitution of Bi-atom with P, As, or Sb atoms significantly enhances the Seebeck coefficient. This enhancement leads to an increase in the power factor value up to ~ 4.69 × 10¹¹ W/m.K².sec for the LuPdBi_0.75Sb_0.25 compound at 700 K. Additionally, Sb doping leads to a decrease in the lattice thermal conductivity, from 4.44 to 1.07 W/m.K for LuPdBi and LuPdBi_0.75Sb_0.25 compounds, respectively. At 700 K, the computed figure of merit (ZT) values for pure and Sb-doped LuPdBi compounds are 0.25 and 0.41, respectively. Our investigation suggests that the LuPdBi compound has the potential as an effective thermoelectric material with suitable Sb doping.