Anomalous Aharonov-Bohm conductance oscillations from topological insulator surface states

TL;DR

This paper predicts that topological insulator nanowires exhibit unique Aharonov-Bohm conductance oscillations with anomalous periods due to surface states and Berry phase effects, especially under strong surface disorder.

Contribution

It introduces the prediction of anomalous AB oscillations in topological insulator nanowires caused by surface states and Berry phase, highlighting the role of surface disorder.

Findings

Anomalous AB oscillations with period $rac{hc}{e}$ predicted

Conductance maxima at odd multiples of $rac{1}{2}rac{hc}{e}$

Surface disorder enhances the visibility of topological signatures

Abstract

We study transport properties of a topological insulator nanowire when a magnetic field is applied along its length. We predict that with strong surface disorder, a characteristic signature of the band topology is revealed in Aharonov Bohm (AB) oscillations of the conductance. These oscillations have a component with anomalous period $\Phi_0=hc/e$, and with conductance maxima at odd multiples of $\frac12\Phi_0$, i.e. when the AB phase for surface electrons is $\pi$. This is intimately connected to the band topology and a surface curvature induced Berry phase, special to topological insulator surfaces. We discuss similarities and differences from recent experiments on Bi$_2$Se$_3$ nanoribbons, and optimal conditions for observing this effect.