Weyl near-field thermal router

What is it about?

By using a non-reciprocal Weyl semi-metal Co3Sn2S2, we have numerically investigated the dynamics of a radiative heat router in a configuration where a hot substrate heats two cold nanoparticles. We demonstrated that a strong spin-spin coupling exists between the localized resonances of nanoparticles and the surface modes of the substrate, particularly in the case of anti-parallel directionality of the Weyl node vectors of the particles and the substrate, resulting in a large transient temperature difference of 22.5% relative to the applied temperature gradient. The effect persists when replacing the nanoparticles with larger objects. Therefore, our findings show the potential for an implementation in a real dynamical experimental setup in the field of thermal management at the nanoscale.

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Photo by Growtika on Unsplash

Photo by Growtika on Unsplash

Why is it important?

One of the challenges in experimentally attaining the routing effect in the previous works is that an accurate control of the positions of 3-nanoscale objects modelled as nanoparticles is typically necessary. The other challenge is that typically magneto-optical materials are used, which require relatively strong magnetic fields of several Tesla in different directions on each particle, again with nanoscale precision. There is a new family of materials called Weyl semi-materials that was recently proposed, which can have a non-reciprocal behaviour without using any external magnetic fields. In our study, we propose to use a simpler setup of two particles in close vicinity to a substrate made of the well-studied Weyl semi-metal Co3Sn2S2. This configuration is much closer to an experimental realization than previously proposed setups. Therewith, our work paves the way for efficient thermal routing at the nanoscale with Weyl semi-metals.