Transport of Massless Dirac Fermions in Non-topological Type Edge States

TL;DR

This paper investigates the conductivity of non-topological Tamm-Shockley edge states in graphene, demonstrating their transport properties through magneto-oscillations and revealing their connection to topological states.

Contribution

It provides the first direct transport measurements of Tamm-Shockley edge states in graphene and links their behavior to topological Dirac fermions.

Findings

Observation of Aharonov-Bohm oscillations in graphene with nanoholes

Evidence of massless Dirac fermion transport in non-topological edge states

Deep connection established between topological and non-topological edge states

Abstract

There are two types of intrinsic surface states in solids. The first type is formed on the surface of topological insulators. Recently, transport of massless Dirac fermions in the band of "topological" states has been demonstrated. States of the second type were predicted by Tamm and Shockley long ago. They do not have a topological background and are therefore strongly dependent on the properties of the surface. We study the problem of the conductivity of Tamm-Shockley edge states through direct transport experiments. Aharonov-Bohm magneto-oscillations of resistance are found on graphene samples that contain a single nanohole. The effect is explained by the conductivity of the massless Dirac fermions in the edge states cycling around the nanohole. The results demonstrate the deep connection between topological and non-topological edge states in 2D systems of massless Dirac fermions.