Ab Initio-Based Band Engineering and Rational Design of Thermoelectric Materials

This chapter summarizes some of our recent work by using density functional ab initio method to understand the Thermoelectric (TE) transport mechanism and help the design of novel TE materials. The key issue on thermoelectric (TE) research is to search for high-efficiency TE materials, which should have high Seebeck coefficient, high electrical conductivity, low thermal conductivity, summation of the electronic part κ_e, and lattice part κ_L, and therefore a reasonably high dimensionless TE figure of merit ZT. Ab initio methods can build knowledge from the study of electrons and atomic nuclei, and investigate the electronic structures of many-body solid systems. Most of the TE materials especially those traditional compounds, are narrow-band semiconductors with some doping. Good TE materials are traditionally considered to be narrow-gap semiconductors. From this point of view, DFT-based band structures can be greatly helpful to a rational search for novel materials. Such an approach has been followed by many people working in the TE community.