Nonclassical heat flow in passive chiral solids is third rank, not odd

TL;DR

This paper demonstrates that passive chiral gyroid lattices exhibit nonclassical heat flow governed by a third rank tensor, challenging the traditional odd second rank tensor model, with implications for tunable thermal metamaterials.

Contribution

It introduces a third rank tensor framework for nonclassical heat flow in passive chiral solids, supported by experimental and theoretical analysis.

Findings

Passive gyroid lattices show nonclassical heat flow incompatible with second rank tensors.

A method to determine the chirality length scale is provided.

Tunable chirality in 3D printed polymer gyroids affects heat flow behavior.

Abstract

Chiral, directionally isotropic gyroid lattices are observed to exhibit nonclassical thermal effects incompatible with an asymmetric ("odd") second rank conductivity tensor but consistent with a third rank tensor property that provides a curl term. The lattices are passive materials so no driving torques are needed to obtain transverse flow. A method for determination of the length scale associated with chirality is provided. The polymer gyroid lattice made by 3D printing is a metamaterial which allows chirality that is tunable by geometry.