Executive Summary : | The conversion of waste heat to electric current opens a new era for thermoelectric materials. A key quantity to know about the thermoelectric performance of a material is a dimensionless figure of merit ZT. Electronon-phonon coupling effects play a crucial role on thermoelectric performance of a material. For a good thermoelectric material, it is essential that it exhibits low lattice thermal conductivity. The lattice thermal conductivity can be minimize by doping of foreign elements. The available reports on several thermoelectric materials such as chalcogenides, skutterudites, silicides, etc show improvement on thermoelectric performance via doping of impurity atoms. The half heusler compounds shows potential for their use in thermoelectric materials due to their high mechanical stability, and low cost. It has been established that the thermoelectric performance of a material can be improved by meal doping, achieving band convergence phenomena, etc. Motivated by these facts I am proposing first principles density functional method based study for a series of high entropy alloys. This project work will be devoted to perform density functional theory based calculations for TiCosb and ZrNisn half heusler compounds with the aim to improve their thermoelectric performance via doping of foreign elements. As a result of which quaternary and higher order compounds will be produced which still have less explored. We will predict first predict structural parameters by using different exchange correlation functional and will compare predicted data with the experimental reported data. When the predicted structural parameters show consistency with the measured results, we shall explain electronic structure in terms of electronic band structure and projected density of states. In order to calculate electronic conductivity, we use Boltzmann transport equation for predicting electronic conductivity, seebeck coefficient, and power factor. Moreover, the lattice thermal conductivity will be explored by phonon spectrum calculations. All the results will be published with combined experimental and theoretical data. The experimental work will be perfumed by experimentalists working in Council of scientific and Industrial Research National Physical Laboratory in New Delhi and accordingly manuscript will be communicated with peer reviewed journals. Besides the proposed work, we will focus on new thermoelectric materials, particularly explaining thermoelectric performance. |