Na2KSb: A Promising Thermoelectric Material

The present study reports the thermoelectric (TE) properties of Na2KSb, and identified it as a promising material for TE applications. The electronic structure calculations are performed using the the full potential linearized augmented plane wave (FP-LAPW) within the frame work of density functional theory, and the transport properties are calculated by solving the Boltzmann transport equation within the constant relaxation time approximation. The obtained lattice parameters are in good agreement with the available experimental and other theoretical results. Thermoelectric properties like thermopower (S), electrical conductivity scaled by relaxation time (sigma/tau) and power-factor (S-2 sigma/tau) are calculated as functions of the carrier concentration and temperature, and both holes and electron doping are found to be favourable at ambient conditions. The effect of hydrostatic compressive and tensile strain on electronic and thermoelectric properties is examined. A significant enhancement in power-factor is observed in the case of electron doping around 10% compressive strain, which might enhance the TE performance.