Thermoelectric properties and anisotropic electronic band structure on the In₄Se_3-x compounds

We report the high thermoelectric figure-of-merit (Z_T) on the Se-deficient polycrystalline compounds of In₄Se_3-x (0.02≤x≤0.5) and the anisotropic electronic band structure. The Se-deficiency (x) has the effect of decreasing the semiconducting band gap and increasing the power factor. The band structure calculation for In₄ Se_3-x (x=0.25) exhibits localized hole bands at the Γ-point and Y-S symmetry line, whereas the significant electronic band dispersion is observed along the c-axis. Here, we propose that the high ZT values on those compounds are originated from the anisotropic electronic band structure as well as Peierls distortion.