Ultrafast helicity control of surface currents in topological insulators with near-unity fidelity
説明
<jats:title>Abstract</jats:title><jats:p>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 Bi<jats:sub>2</jats:sub>Se<jats:sub>3</jats:sub> 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.</jats:p>
収録刊行物
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- Nature Communications
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Nature Communications 6 (1), 6617-, 2015-03-26
Springer Science and Business Media LLC
