Robustness of the helical edge states in topological insulators

TL;DR

This paper investigates the robustness of helical edge states in topological insulators, specifically Bi2Se3, using first principles calculations to quantify how disorder affects their conductive properties.

Contribution

It provides a detailed atomistic analysis of disorder scattering effects on helical states in Bi2Se3, revealing how potential strength and distribution impact their robustness.

Findings

Robustness varies with disorder strength and spatial distribution.

Certain scattering configurations significantly disrupt helical states.

Quantitative assessment of disorder effects on topological surface states.

Abstract

Topological insulators (TI) are materials having an energy band gap in the bulk and conducting helical electronic states on the surface. The helical states are protected by time reversal symmetry thus are expected to be robust against static disorder scattering. In this work we report atomistic first principles analysis of disorder scattering in two-probe transport junctions made of three dimensional TI material Bi2Se3. The robustness of the device against disorder scattering is determined quantitatively. Examining many different scattering configurations, a general trend emerges on how strong the perturbing potential and how it is spatially distributed that can derail the helical states on the Bi2Se3 surfaces.