General Strategy for Large Nernst Coefficient

TL;DR

The paper addresses the problem of small anomalous Nernst coefficients in ferromagnets and proposes a general strategy based on the Sommerfeld-Bethe relation to guide enhancements of the anomalous Nernst response. It develops a theoretical framework that connects electronic structure to the anomalous Nernst coefficient $S_{xy}$ and introduces a Mahan-Sofo-type strategy to identify favorable conditions for large $S_{xy}$. Key contributions include the derivation of the Sommerfeld-Bethe relation, a principled design approach for enhancing $S_{xy}$, and illustrative simplified models that realize substantially larger Nernst responses. The work provides a systematic route for designing ferromagnetic thermoelectrics with materially larger anomalous Nernst effects, with potential impact on energy conversion and thermal sensing technologies.

Abstract

We propose a general strategy for enhancing the anomalous Nernst coefficient based on the Sommerfeld-Bethe relation. This approach provides a systematic framework for understanding the small anomalous Nernst coefficients typically observed in ferromagnets and identifies conditions under which substantial enhancements can be realized. We further introduce simplified models that exhibit large Nernst coefficients as offering illustrative examples.