INVESTIGATION OF PHYSICAL PROPERTIES OF NATISB HALFHEUSLER FOR GREEN ENERGY APPLICATIONS

Alternative sources of clean energy are essential in view of the growing global demand for energy and its impact on the environment. Thermoelectric (TE) technology has been discovered to be the ideal answer to these problems because it can convert heat directly into electricity without producing noise and emitting CO2. However, the commercial use of TE materials is limited due to their low conversion efficiency. For a material to be suitable for TE applications it must have a figure of merit (zT) greater than one. Fortunately, Heusler compounds have been shown to be good TE materials. Thus, the purpose of this research is to find materials with promising thermoelectric properties that will be suitable for TE applications. The structural stability, electronic, magnetic and thermoelectric properties are scrutinized using the full potential-linearized augment plane wave (FP-LAPW) approach and classical Boltzmann approximations in the density functional theory (DFT) as implemented within WIEN2K computational code. The results predicted for structural properties reveal that NaTiSb is stable in the ferromagnetic type-α phase. The electronic behavior reveal that this material is half-metallic, with metallic nature in the up spin and an indirect band gap semiconducting behavior along the down-spin channel. The data of thermoelectric zT found for NaTiSb is 0.73 eV at 300 K, suggesting its suitability for thermoelectric applications.