Criteria for realizing room temperature electrical transport applications of topological materials

TL;DR

This paper establishes key criteria based on atomic and electronic properties to identify topological materials suitable for room temperature electronic applications, aiming to overcome bulk conduction issues.

Contribution

It provides a clear set of material criteria involving band gap, dielectric constant, and effective mass to guide the discovery of topological materials with dominant surface states.

Findings

Key parameters determine bulk vs. surface conduction balance.

Chemical arguments can predict material suitability.

Criteria enable rapid identification of promising topological materials.

Abstract

The unusual electronic states found in topological materials can enable a new generation of devices and technologies, yet a long-standing challenge has been finding materials without deleterious parallel bulk conduction. This can arise either from defects or thermally activated carriers. Here, I clarify the criteria that materials need to meet to realize transport properties dominated by the topological states, a necessity for a topological device. This is demonstrated for 3-dimensional topological insulators, 3D Dirac materials, and 1D quantum anomalous Hall insulators, though this can be applied to similar systems. The key parameters are electronic band gap, dielectric constant, and carrier effective mass, which dictate under what circumstances (defect density, temperature, etc.) the unwanted bulk state will conduct in parallel to the topological states. As these are fundamentally determined by the basic atomic properties, simple chemical arguments can be used to navigate the phase space to ultimately find improved materials. This will enable rapid identification of new systems with improved properties, which is crucial to design new materials systems and push into a new generation of topological technologies.