Weyl Fermion magneto-electrodynamics and ultralow field quantum limit in TaAs
Author(s)
Lu, Zhengguang; Hollister, Patrick; Ozerov, Mykhaylo; Moon, Seongphill; Bauer, Eric D; Ronning, Filip; Smirnov, Dmitry; Ju, Long; Ramshaw, BJ; ... Show more Show less
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Topological semimetals are predicted to exhibit unconventional electrodynamics, but a central experimental challenge is singling out the contributions from the topological bands. TaAs is the prototypical example, where 24 Weyl points and 8 trivial Fermi surfaces make the interpretation of any experiment in terms of band topology ambiguous. We report magneto-infrared reflection spectroscopy measurements on TaAs. We observed sharp inter-Landau level transitions from a single pocket of Weyl Fermions in magnetic fields as low as 0.4 tesla. We determine the W2 Weyl point to be 8.3 meV below the Fermi energy, corresponding to a quantum limit—the field required to reach the lowest LL—of 0.8 tesla—unprecedentedly low for Weyl Fermions. LL spectroscopy allows us to isolate these Weyl Fermions from all other carriers in TaAs, and our result provides a way for directly exploring the more exotic quantum phenomena in Weyl semimetals, such as the chiral anomaly.
Date issued
2022-01-14Department
Massachusetts Institute of Technology. Department of PhysicsJournal
Science Advances
Publisher
American Association for the Advancement of Science (AAAS)
Citation
Lu, Zhengguang, Hollister, Patrick, Ozerov, Mykhaylo, Moon, Seongphill, Bauer, Eric D et al. 2022. "Weyl Fermion magneto-electrodynamics and ultralow field quantum limit in TaAs." Science Advances, 8 (2).
Version: Final published version