Regensburg 2019 – scientific programme
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DS: Fachverband Dünne Schichten
DS 3: Layer Properties: Electronic, Optical and Mechanical Properties
DS 3.5: Talk
Monday, April 1, 2019, 10:30–10:45, H39
Photo-induced anomalous Hall effect in the type-II Weyl-semimetal WTe 2 at room-temperature — Paul Seifert1, Florian Sigger1,2, Jonas Kiemle1, Kenji Watanabe3, Takashi Taniguchi3, Christoph Kastl4, •Philipp Bootz1, Ursula Wurstbauer1,2, and Alexander Holleitner1,2 — 1Walter Schottky Institut and Physics Department, Technical University of Munich, Am Coulombwall 4a, 85748 Garching, Germany — 2Nanosystems Initiative Munich (NIM), Schellingstr. 4, 80799 München, Germany — 3Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan — 4Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Road, 94720 Berkeley, California, United States
Using Hall photovoltage measurements, we demonstrate that an anomalous Hall (AH) 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 AH 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. We find that the decay time of the AH 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 AHE.