Directional control of diffusion phenomena using topological insulators

A study conducted by Keita Funayama et al. in collaboration with Kyoto University was published in the Communications Physics.

Directional control of diffusion phenomena is an innovative technology that realizes functional improvements in various engineering fields, such as thermal management and diffusive particle control. However, directional control in pure diffusion systems is difficult because dispersive phenomena such as diffusion progress in all directions in space. This study investigated the thermal diffusion behavior in topological insulators comprising hexagonal unit cells. In a structure inspired by quantum phenomena, unusual temperature distributions called topological edge modes appeared. We found that the unit cells induce unidirectional thermal diffusion in only the horizontal or vertical direction because of initial temperature distributions of the edge modes. In addition, with time evolution, the unidirectional heat flow results in thermal polarization in a finite periodic structure. The selectable diffusion direction contributes to heat recovery, thermal transport systems, and selective separation/induction of micro/nano particles.

Title: Selectable Diffusion Direction with Topologically Protected Edge Modes
Authors: Funayama, K., Hirotani, J., Miura, A., Tanaka, H.
Journal Name: Communications Physics
Published: December 20, 2023
https://doi.org/10.1038/s42005-023-01490-9