Subnanometre-wide electron channels protected by topology

Pauly C, Rasche B, Koepernik K, Liebmann M, Pratzer M, Richter M, Kellner J, Eschbach M, Kaufmann B, Plucinski L, Schneider CM, Ruck M, Van Den Brink J, Morgenstern M (2015)

Publication Type: Journal article

Publication year: 2015

Journal

Nature Physics Nature Research

Book Volume: 11

Pages Range: 338-343

Journal Issue: 4

DOI: 10.1038/nphys3264

Abstract

Helical locking of spin and momentum and prohibited backscattering are the key properties of topologically protected states. They are expected to enable novel types of information processing by providing pure spin currents, or fault tolerant quantum computation by using the Majorana fermions at interfaces of topological states with superconductors. So far, the required helical conduction channels used to realize Majorana fermions are generated through the application of an axial magnetic field to conventional semiconductor nanowires. Avoiding the magnetic field enhances the possibilities for circuit design significantly. Here, we show that subnanometre-wide electron channels with natural helicity are present at surface step edges of the weak topological insulator Bi 14 Rh 3 I 9 (ref.). Scanning tunneling spectroscopy reveals the electron channels to be continuous in both energy and space within a large bandgap of 200 meV, evidencing its non-trivial topology. The absence of these channels in the closely related, but topologically trivial compound Bi 13 Pt 3 I 7 corroborates the channels'topological nature. The backscatter-free electron channels are a direct consequence of Bi 14 Rh 3 I 9 's structure: a stack of two-dimensional topologically insulating, graphene-like planes separated by trivial insulators. We demonstrate that the surface of Bi 14 Rh 3 I 9 can be engraved using an atomic force microscope, allowing networks of protected channels to be patterned with nanometre precision.

Involved external institutions

Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen DE Germany (DE) Technische Universität Dresden DE Germany (DE) Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden e.V. (IFW) / Leibniz Institute for Solid State and Materials Research Dresden DE Germany (DE) Forschungszentrum Jülich / Research Centre Jülich (FZJ) DE Germany (DE)

How to cite

APA:

Pauly, C., Rasche, B., Koepernik, K., Liebmann, M., Pratzer, M., Richter, M.,... Morgenstern, M. (2015). Subnanometre-wide electron channels protected by topology. Nature Physics, 11(4), 338-343. https://doi.org/10.1038/nphys3264

MLA:

Pauly, Christian, et al. "Subnanometre-wide electron channels protected by topology." Nature Physics 11.4 (2015): 338-343.

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