Prediction of the thermoelectric properties of half-Heusler phases from the density functional theory

The Half-Heusler phases within the Density Functional Theory (DFT) could be divided into three parts. The first part consists of chemical bonding evaluation using semi-empirical extended Hückel tight-binding method. The second part contains thermodynamic calculations using heat of formation obtained from the total energy calculations and temperature dependences of the entropy, free energy and enthalpy from phonon calculations in quasiharmonic approximation. The third part includes physical properties calculation using the linear response techniques in Korringa-Kohn-Rostocker method with Coherent Potential Approximation and analysis of Density of States spectrum (DOS). The interpretation of the chemical bonding is made via the analysis of the distribution of the DOS and defining the overlapping states of each element. The complex utilization of different DFT methods allows predicting the main thermoelectric properties of half-Heusler materials. Combination of theoretical DFT methods with experimental techniques gives the key for better understanding the nature of thermoelectric phenomena in half-Heusler materials.