Desirable dopants for thermoelectrics

Doping is a common technique to achieve good electrical conduction in semiconductors, and is often used to optimize the performance of thermoelectric materials. While its effect on the electron mobility has been widely appreciated, the understandings still mostly rely on simplified models, which often neglect the chemical details of the dopants. On the other hand, experimental evidence has suggested that dopants with different chemical nature can behave quite differently. The lack of theory to explain such observations, however, has impeded our understanding for controlling dopants, and defects in general, for thermoelectric materials. Recently we have developed a first principles approach to quantitatively evaluate the the effects of dopants on the electron transport. We will discuss how the bonding environment of the atoms - a previously overlooked aspect - can significantly affect the electron transport. The study potentially provides guidelines for finding efficient dopants for thermoelectric materials.