Temperature profile of the Thomson-effect-induced heat release/absorption in junctionless single conductors

Abstract

The Thomson effect induces heat release or absorption under the simultaneous application of a charge current and a temperature gradient to conductors. Although a thermoelectric Thomson device can be a simple temperature modulator without constructing heterojunction structure, in contrast to the Seebeck and Peltier effects, the thermoelectric performance of the Thomson effect driven by an external temperature difference has not been formulated so far. Here, we present an efficiency formula, i.e., coefficient of performance (COP) for the Thomson device. Based on the formulation, we find that COP of the Thomson device is characterized not only by the Thomson coefficient but also by the Seebeck coefficient. We show that the Thomson device can exhibit large COP for the cooling operation even if the conductor has a small Seebeck coefficient. We also present a more realistic discussion on COP of the Thomson device with material parameters. The proposed formula will provide a new guideline for finding thermoelectric materials.