Band structure engineering through orbital interaction for enhanced thermoelectric power factor

Band structure engineering for specific electronic or optical properties is essential for the further development of many important technologies including thermoelectrics, optoelectronics, and microelectronics. In this work, we report orbital interaction as a powerful tool to finetune the band structure and the transport properties of charge carriers in bulk crystalline semiconductors. The proposed mechanism of orbital interaction on band structure is demonstrated for IV-VI thermoelectric semiconductors. For IV-VI materials, we find that the convergence of multiple carrier pockets not only displays a strong correlation with the s-p and spin-orbit coupling but also coincides with the enhancement of power factor. Our results suggest a useful path to engineer the band structure and an enticing solid-solution design principle to enhance thermoelectric performance.Swedish Research Council ((VR) Grant No. 621-2011-4249)Swedish Research Council (Linnaeus Environment at Linkoping on Nanoscale Functional Materials (LiLi-NFM))United States. Office of Naval Research (Contract No. N00014-11-1-0212