Stability and Thermoelectric Properties of Transition-Metal Silicides

We report an ab initio study of the stability and electronic properties of several transition-metal silicides in order to investigate their potential for high-temperature thermoelectric applications. We focus on two different families, i.e., M5Si3 and MSi (M = transition metal), which are stable up to about 2000°C and 1300°C, respectively. We show that electron-doped CoSi can be quantitatively described in the rigid band approximation and that Mott’s law can also be applied. Our conclusions indicate that CoSi needs further investigation of its thermoelectric potential for high-temperature applications, because it is still not optimized. Using a similar approach, we have shown that W5Si3 could have a relatively large thermopower, but it is probably not sufficient for thermoelectric applications.