Helical Luttinger liquid in topological insulator nanowires

TL;DR

This paper develops a low-energy theory for electrons in topological insulator nanowires, revealing a topologically protected helical Luttinger liquid state that can be detected via transport experiments.

Contribution

It introduces a comprehensive theoretical framework for the helical Luttinger liquid in topological insulator nanowires, highlighting its topological protection and experimental signatures.

Findings

Identification of a helical Luttinger liquid state in nanowires

Topological protection against weak disorder

Proposals for experimental detection via transport measurements

Abstract

We derive and analyze the effective low-energy theory for interacting electrons in a cylindrical nanowire made of a strong topological insulator. Three different approaches provide a consistent picture for the band structure, where surface states forming inside the bulk gap correspond to one-dimensional bands indexed by total angular momentum. When a half-integer magnetic flux pierces the nanowire, we find a strongly correlated helical Luttinger liquid topologically protected against weak disorder. We describe how transport experiments can detect this state.