Near-field photon Nernst effect

TL;DR

This paper introduces a photon Nernst effect in a graphene-magneto-optical system caused by nonreciprocal photon transfer under a temperature gradient, with potential applications in energy harvesting.

Contribution

It demonstrates the existence of a transverse electric field induced by nonreciprocal Casimir forces in a graphene-based system, linking near-field radiative transfer to thermoelectric effects.

Findings

Photon Nernst effect is driven by nonreciprocal Casimir forces.

Thermal efficiency is bounded by the Carnot limit.

High-k modes are essential for approaching maximum efficiency.

Abstract

We consider the consequence of having nonreciprocal photon transfer between two surfaces with temperature gradient. We demonstrate that in a system consisting of graphene and a magneto-optical substrate separated by a gap, a transverse electric field is generated in graphene perpendicular to magnetic field and temperature gradient, in analogy to Nernst effect. Such photon Nernst effect is driven by nonreciprocal Casimir force carried by photons. We show that the thermal efficiency of near-field photon Nernst effect is bounded by the Carnot limit, and nonreciprocal high-k modes are needed for approaching the limit. The near-field photon Nernst effect can be useful for probing nonreciprocal radiative transfer, and energy harvesting.