Dual Topological Insulator Device with Disorder Robustness

TL;DR

This paper investigates the robustness of edge states in Na$_3$Bi, a dual topological insulator, under disorder and defects, proposing a device that maintains stable conductance across temperatures by defect engineering.

Contribution

It introduces a recursive Green's function method to analyze disordered Na$_3$Bi and proposes a novel device design leveraging intrinsic defects for stable topological conductance.

Findings

Edge states remain robust despite intrinsic defects.

Defect engineering enables filtering of trivial bulk states.

Device maintains conductance stability over temperature range.

Abstract

Two-dimensional Na$_3$Bi is a dual topological insulator protected by time-reversal and mirror symmetry, resulting in a promising platform for devices design. However, in reality, the design of topological devices is hindered by a sensitivity against disorder and temperature. We study the topological properties of Na$_3$Bi in the presence of intrinsic defects, investigating the robustness of the edge states and the resulting transport properties. We apply a recursive Green's function technique enabling the study of disordered systems with lengths comparable to experimentally synthesized materials, in the order of micrometers. We combine our findings to propose a topological insulator device, where intrinsic defects are used to filter the response of trivial bulk states. This results in a stable conductance throughout a large range of electronic temperatures, and controllable by a perpendicular electric field. Our proposal is general, enabling the design of various dual topological insulators devices.