Anisotropy Effects on the Thermoelectric Electronic Transport Coefficients

Abstract

Engineering thermoelectric (TE) materials for applications in power generation and cooling requires an understanding of how anisotropy influences the TE properties. In this paper we use an angular-dependent, multivalley formalism to model the band structure and to explore the effect of anisotropy on the Seebeck and conductivity tensors. Specifically we explore the effect of degeneracy and relative orientation of the effective mass ellipsoids near critical points on the shape of these tensors. Examples of these types of anisotropic effects are explored within the above formalism and with the full band structures of two materials: half-Heusler ZrNiSn and (Sr,Ba) Nb2O6 with the tetragonal tungsten bronze structure.