ICT2014 Abstracts

We have employed a different approach than relaxation time approximation for Boltzmann Transport Equation (BTE) generally used for thermoelectric electronic properties calculation. In this method, we used ab initio DFT calculation results to calculate s-p-d wave function admixture, the effective mass, electron/hole group velocity and conduction/valence band energy eigenvalues which are direct results of DFT calculation. The parameters are predicted from DFT rather than using methods commonly used in the literature such as k.p method or experimental data. The results were then used to calculate elastic electron/hole scattering rates of ionized impurity scattering with a special importance in doped thermoelectrics, piezoelectric scattering, deformation potential scattering, and charged lattice dislocation scattering mechanism with special importance in imperfect crystals. The parameters were also used to iteratively solve BTE for the perturbed carrier distribution which is a result of inelastic scattering mechanism (i.e. polar optical phonon scattering) in the material. We studied the effect of these scattering mechanisms on zinc antimonide, β-Zn4Sb3, and found a limit for its power factor based on different defect concentrations and their effect on carrier scattering.