# Absence of strong localization at low conductivity in the topological surface state of low disorder Sb2Te3

## TL;DR

This study investigates the transport properties of a high-mobility, low-disorder topological insulator, revealing the absence of strong localization at low conductivities and providing insights into surface state hybridization and disorder.

## Contribution

It demonstrates that strong localization does not occur at low conductivities in topological surface states, challenging conventional expectations and offering a detailed analysis of disorder effects.

## Key findings

- No strong localization at conductivities below e^2/h
- Temperature behavior of localization peak differs from conventional models
- Quantitative estimates of disorder potential and surface state hybridization

## Abstract

We present low-temperature transport measurements of a gate-tunable thin film topological insulator system that features high mobility and low carrier density. Upon gate tuning to a regime around the charge neutrality point, we infer an absence of strong localization even at conductivities well below $e^2/h$, where two dimensional electron systems should conventionally scale to an insulating state. Oddly, in this regime the localization coherence peak lacks conventional temperature broadening, though its tails do change dramatically with temperature. Using a model with electron-impurity scattering, we extract values for the disorder potential and the hybridization of the top and bottom surface states.