One-dimensional channel for Dirac electrons in a 3D topological insulator

TL;DR

This paper reports the discovery of one-dimensional topographic stripes on a topological insulator surface that modulate Dirac electron states, enabling potential realization of 1D chiral modes and dissipationless quantum wires.

Contribution

It introduces a novel intrinsic topographic mechanism to control Dirac electron properties in topological insulators, facilitating the creation of 1D chiral modes.

Findings

Identification of 1D topographic stripes on Bi2Te3 surface.

Observation of Landau level energy modulation along stripes.

Potential for realizing topological 1D chiral modes.

Abstract

Topological insulators represent a new state of matter where the topological nature of the bulk bands dictates the existence of a surface state with unique properties. These materials are predicted to host exotic states such as Majorana Fermions and 1D chiral modes, many of which require a delicate tuning of the surface state properties near the Dirac point. Using scanning tunneling microscopy (STM) on the prototypical topological insulator Bi2Te3, we have discovered one-dimensional topographic stripes which induce spatially modulated changes in the electronic structure. Direct magnetic field measurements reveal a striped pattern of Landau level energies, which can be used to realize spatial regions with alternating filling fractions. When the chemical potential is properly tuned, the observed modulation would dictate the existence of topological 1D chiral modes at the boundaries between the stripes, and provide a platform for the experimental realization of 1D dissipationless quantum wires in topological insulators. Our discovery that the surface state dispersion is modulated over nanometer length scales by an intrinsic topographic route represents a new paradigm for controlling the properties of Dirac electrons.