Spinodal superlattices of topological insulators

TL;DR

This paper proposes using spinodal decomposition to create stable, self-assembled topological insulator interfaces, enabling the formation of 2D conducting channels within insulating materials for potential technological applications.

Contribution

It introduces a novel approach to stabilize topological insulator interfaces via spinodal decomposition, allowing for controlled formation of 2D TI channels embedded in 3D insulators.

Findings

Spinodal superlattices can be formed in TlBiS2-TlBiTe2 systems.

The topological nature of metallic channels depends on composition and spatial distribution.

Spontaneous formation of 2D TI channels embedded in 3D insulators is demonstrated.

Abstract

Spinodal decomposition is proposed for stabilizing self-assembled interfaces between topological insulators (TIs) by combining layers of iso-structural and iso-valent TlBi$X_2$ ($X$=S, Se, Te) materials. The composition range for gapless states is addressed concurrently to the study of thermodynamically driven boundaries. By tailoring composition, the TlBiS$_2$-TlBiTe$_2$ system might produce both spinodal superlattices and two dimensional eutectic microstructures, either concurrently or separately. The dimensions and topological nature of the metallic channels are determined by following the spatial distribution of the charge density and the spin-texture. The results validate the proof of concept for obtaining spontaneously forming two-dimensional TI-conducting channels embedded into three-dimensional insulating environments without any vacuum interfaces. Since spinodal decomposition is a controllable kinetic phenomenon, its leverage could become the long-sought enabler for effective TI technological deployment.