Beyond the constant relaxation time*

Over the years, first principles calculations have become a complementary tool for the experimental research aiming to discover high-performance thermoelectrics. This has greatly improved the understanding of the transport properties and has advanced optimization strategies based on “band engineering” [1,2]. In most cases, the constant relaxation time approximation has been used without much analysis. We investigated the limits of the approximations for the relaxation time in the electronic transport coefficients properties of well know TE materials by considering different models that include energy and temperature dependence. Transport coefficients have been computed using the recently developed PAOFLOW package (http://aflowlib.org/src/paoflow/).