Observation of transverse Thomson effect

TL;DR

This paper reports the first experimental observation of the transverse Thomson effect in a conductor, revealing new insights into thermoelectric phenomena and enabling advanced thermal management applications.

Contribution

The study provides the first experimental evidence of the transverse Thomson effect, distinguishing it from the conventional effect and highlighting its dependence on the Nernst coefficient.

Findings

Volumetric heating/cooling observed in BiSb alloy under orthogonal current, temperature gradient, and magnetic field.

The effect can be switched by changing the magnetic field direction.

The transverse Thomson effect depends on both the magnitude and temperature derivative of the Nernst coefficient.

Abstract

The thermoelectric Thomson effect, predicted in the 1850s by William Thomson, produces volumetric heating/cooling in a conductor due to the concerted action of the Seebeck and Peltier effects. Recently, transverse thermoelectrics studies on the Nernst and Ettingshausen effects have progressed rapidly to enable versatile thermal management technologies and to explore topological transport properties. However, a transverse Thomson effect, arising from the concerted action of the Nernst and Ettingshausen effects, has not yet been observed. Here, we report the observation of the transverse Thomson effect in a conductor. We observed volumetric heating/cooling in a semimetallic Bi$_{88}$Sb$_{12}$ alloy induced by a charge current, temperature gradient, and magnetic field applied orthogonally to each other using thermoelectric imaging techniques. We found that the heating/cooling can be switched by the field direction. Our experiments and analyses reveal the essential difference between the conventional and transverse Thomson effects; the former depends sorely on the temperature derivative of the Seebeck coefficient, while the latter depends not only on the temperature derivative of the Nernst coefficient but also on its magnitude. The observation of the transverse Thomson effect fills a missing piece in the history of thermoelectrics and provides a new principle for active thermal management technologies.