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arXiv · 1810.01510

Photo-induced anomalous Hall effect in the type-II Weyl-semimetal WTe2 at room-temperature

Paul Seifert·Florian Sigger·Jonas Kiemle·Kenji Watanabe·Takashi Taniguchi·Christoph Kastl·Ursula Wurstbauer·Alexander Holleitner
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Abstract

Using Hall photovoltage measurements, we demonstrate that an anomalous Hall-voltage can be induced in few layer WTe2 under circularly polarized light illumination. By applying a bias voltage along different crystal axes, we find that the photo-induced anomalous Hall conductivity coincides with a particular crystal axis. Our results are consistent with the underlying Berry-curvature exhibiting a dipolar distribution due to the breaking of crystal inversion symmetry. Using a time-resolved optoelectronic auto-correlation spectroscopy, we find that the decay time of the anomalous Hall voltage exceeds the electron-phonon scattering time by orders of magnitude but is consistent with the comparatively long spin-lifetime of carriers in the momentum-indirect electron and hole pockets in WTe2. Our observation suggests, that a helical modulation of an otherwise isotropic spin-current is the underlying mechanism of the anomalous Hall effect.

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Paul Seifert, Florian Sigger, Jonas Kiemle, Kenji Watanabe, Takashi Taniguchi, Christoph Kastl, Ursula Wurstbauer, Alexander Holleitner. 2018-10-02. Photo-induced anomalous Hall effect in the type-II Weyl-semimetal WTe2 at room-temperature. https://doi.org/10.1103/physrevb.99.161403

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