First-principle Calculations of Pisarenko Relation and Hall Factor in Thermoelectric Materials

Abstract

The Pisarenko relation, which is used to measure the density of state effective mass in thermoelectrical research, has limits, as it is not able to reflect anisotropy and degeneracy of band structure properly. The main objective of this master thesis is improving the method through the ab-initio computation of thermoelectric(TE) properties in TE materials. This improvement is performed in two directions. First, by proposing the improved Pisarenko relation that reflects the energy dispersion properties from the first-principle thermoelectric properties. Secondly, hall factors are suggested to measure the carrier concentration more accurately from the Hall measurement. In addition, a second-order fitting equation is provided to obtain the Hall factors easily. These is given for typical thermoelectric materials : Bi2Te3, Bi2Se3, Sb2Te3, CoSb3, Mg2Si, PbTe and SnSe.