Dresden 2017 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 76: Topological Insulators II (joined session with TT)
HL 76.1: Talk
Thursday, March 23, 2017, 14:45–15:00, POT 251
Visualizing the response of Weyl semimetals to Coulomb and magnetic perturbations — •Thomas Bathon1, Paolo Sessi1, Yan Sun2, Florian Glott1, Zhilin Li3, Hongxiang Chen3, Liwei Guo3, Xialong Chen3, Markus Schmidt2, Claudia Felser2, Binghai Yan2, and Matthias Bode1 — 1Experimentelle Physik II der Universität Würzburg, Würzburg — 2Max Planck Institute for Chemical Physics of Solids, Dresden — 3Institute of Physics at the Chinese Academy of Sciences, Peking
Weyl semimetals are a new class of topological materials which led to the emergence of Weyl physics in condensed matter. While photoemission successfully identified Weyl surface states with unique Fermi arcs, their fundamental microscopic properties, such as scattering mechanisms, persistence of spin-coherence, and the reaction to external perturbations, have not been widely investigated so far.
Here, we use TaAs to address these important aspects at the atomic scale by scanning tunneling microscopy and spectroscopy. We deliberately introduce external adatoms to test the response of this class of materials to well-defined Coulomb and magnetic perturbations. We demonstrate that, contrary to topological insulators, they are effectively screened in Weyl semimetals. Our analysis demonstrates that intra- as well as inter-Fermi arc scattering events are strongly suppressed. Additionally, we show that the existence of large parallel segments of spin-split trivial states facing each other makes possible, through scattering, to revert both the propagation direction while simultaneously flipping the spin state, strongly limiting its coherence.