The Limits of Thermoelectric Performance with a Bounded Transport Distribution

Abstract

With the goal of maximizing the thermoelectric (TE) figure of merit $ZT$, Mahan and Sofo [Proc. Natl. Acad. Sci. U.S.A. 93, 7436 (1996)] found that the optimal transport distribution (TD) is a delta function. Materials, however, have TDs that appear to always be finite and non-diverging. Motivated by this observation, this study focuses on deriving what is the optimal bounded TD, which is determined to be a boxcar function for $ZT$ and a Heaviside function for power factor. From these optimal TDs upper limits on $ZT$ and power factor are obtained; the maximum $ZT$ scales with ${\Sigma }_{\max }T/{\kappa }_l$, where ${\Sigma }_{\max }$ is the TD magnitude and ${\kappa }_l$ is the lattice thermal conductivity. These results help establish practical upper limits on the performance of TE materials and provide target TDs to guide band/scattering engineering strategies.

7 pages, 3 figures

References in corpus (3)

• Electronic structure and thermoelectric properties of n- and p-type SnSe from first principles calculations
• Band alignment and scattering considerations for enhancing the thermoelectric power factor of complex materials: The case of Co-based half-Heuslers
• Ultra-High Thermoelectric Power Factors in Narrow Gap Materials with Asymmetric Bands

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