One-dimensional topological edge states of bismuth bilayers

The hallmark of a topologically insulating state of matter in two dimensions protected by time-reversal symmetry is the existence of chiral edge modes propagating along the perimeter of the sample. Among the first systems predicted to be a two-dimensional topological insulator are bilayers of bismut...

Full description

Saved in:
Bibliographic Details
Published in:Nature physics 2014-09, Vol.10 (9), p.664-669
Main Authors: Drozdov, Ilya K., Alexandradinata, A., Jeon, Sangjun, Nadj-Perge, Stevan, Ji, Huiwen, Cava, R. J., Andrei Bernevig, B., Yazdani, Ali
Format: Article
Language:English
Subjects:
136/138
639/766/119/1000/1018
639/766/119/2792
639/766/119/995
Atomic
Backscattering
Bismuth
Classical and Continuum Physics
Coherent scattering
Complex Systems
Condensed Matter Physics
Crystals
Insulators
Mathematical and Computational Physics
Microscopy
Molecular
Optical and Plasma Physics
Physics
Propagation
Quantum physics
Theoretical
Topology
Two dimensional
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The hallmark of a topologically insulating state of matter in two dimensions protected by time-reversal symmetry is the existence of chiral edge modes propagating along the perimeter of the sample. Among the first systems predicted to be a two-dimensional topological insulator are bilayers of bismuth. Here we report scanning tunnelling microscopy experiments on bulk Bi crystals that show that a subset of the predicted Bi-bilayers’ edge states are decoupled from the states of the substrate and provide direct spectroscopic evidence of their one-dimensional nature. Moreover, by visualizing the quantum interference of edge-mode quasi-particles in confined geometries, we demonstrate their remarkable coherent propagation along the edge with scattering properties consistent with strong suppression of backscattering as predicted for the propagating topological edge states. The conducting surface states of 3D topological insulators are two-dimensional. In an analogous way, the edge states of 2D topological insulators are one-dimensional. Direct evidence of this one-dimensionality is now presented, by means of scanning tunnelling spectroscopy, for bismuth bilayers—one of the first theoretically predicted 2D topological insulators.
ISSN:1745-2473
1745-2481
DOI:10.1038/nphys3048