Selectable diffusion direction with topologically protected edge modes

TL;DR

This paper demonstrates that topologically protected edge modes in a honeycomb structure can be used to control and select the direction of thermal diffusion, with robustness against defects due to topological protection.

Contribution

It introduces a method to control thermal diffusion direction using topological edge modes via the quantum spin Hall effect in a honeycomb structure.

Findings

Thermal diffusion direction can be tuned by setting temperature to specific edge modes.

The diffusion system is robust against structural defects.

Topological states enable defect-immune control of diffusion.

Abstract

Topological insulators provide great potentials to control diffusion phenomena as well as waves. Here, we show that the direction of thermal diffusion can be selected by the contributions of the topologically protected edge modes via the quantum spin Hall effect in a honeycomb-shaped structure. We demonstrate that when we set our structure to the temperature corresponding to the type of edge mode, the direction of thermal diffusion can be tuned. Moreover, this diffusion system is found to be immune to defects owing to the robustness of topological states. Our work points to exciting new avenues for controlling diffusion phenomena.