Ultrafast helicity control of surface currents in topological insulators with near-unity fidelity

  • In recent years, a class of solid-state materials, called three-dimensional topological insulators, has emerged. In the bulk, a topological insulator behaves like an ordinary insulator with a band gap. At the surface, conducting gapless states exist showing remarkable properties such as helical Dirac dispersion and suppression of backscattering of spin-polarized charge carriers. The characterization and control of the surface states via transport experiments is often hindered by residual bulk contributions. Here we show that surface currents in Bi2Se3 can be controlled by circularly polarized light on a picosecond timescale with a fidelity near unity even at room temperature. We reveal the temporal separation of such ultrafast helicity-dependent surface currents from photo-induced thermoelectric and drift currents in the bulk. Our results uncover the functionality of ultrafast optoelectronic devices based on surface currents in topological insulators.

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Author:Christoph Kastl, Christoph Karnetzky, Helmut KarlORCiDGND, Alexander W. Holleitner
Frontdoor URLhttps://opus.bibliothek.uni-augsburg.de/opus4/110091
Parent Title (English):Nature Communications
Publisher:Springer Science and Business Media LLC
Date of first Publication:2015/03/26
Publishing Institution:Universität Augsburg
Release Date:2023/12/12
Tag:General Physics and Astronomy; General Biochemistry, Genetics and Molecular Biology; General Chemistry
First Page:6617
Institutes:Mathematisch-Naturwissenschaftlich-Technische Fakultät
Mathematisch-Naturwissenschaftlich-Technische Fakultät / Institut für Physik
Mathematisch-Naturwissenschaftlich-Technische Fakultät / Institut für Physik / Lehrstuhl für Experimentalphysik IV
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik
Licence (German):CC-BY 4.0: Creative Commons: Namensnennung (mit Print on Demand)