Z2 and Chiral Anomalies in Topological Dirac Semimetals

Anton A. Burkov and Yong Baek Kim
Phys. Rev. Lett. 117, 136602 – Published 21 September 2016

Abstract

We demonstrate that topological Dirac semimetals, which possess two Dirac nodes, separated in momentum space along a rotation axis and protected by rotational symmetry, exhibit an additional quantum anomaly, distinct from the chiral anomaly. This anomaly, which we call the Z2 anomaly, is a consequence of the fact that the Dirac nodes in topological Dirac semimetals carry a Z2 topological charge. The Z2 anomaly refers to nonconservation of this charge in the presence of external fields due to quantum effects and has observable consequences due to its interplay with the chiral anomaly. We discuss possible implications of this for the interpretation of magnetotransport experiments on topological Dirac semimetals. We also provide a possible explanation for the magnetic field dependent angular narrowing of the negative longitudinal magnetoresistance, observed in a recent experiment on Na3Bi.

  • Figure
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  • Received 4 July 2016

DOI:https://doi.org/10.1103/PhysRevLett.117.136602

© 2016 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Anton A. Burkov1,2 and Yong Baek Kim3,4

  • 1Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
  • 2ITMO University, Saint Petersburg 197101, Russia
  • 3Department of Physics and Center for Quantum Materials, University of Toronto, Toronto, Ontario M5S 1A7, Canada
  • 4Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada

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Issue

Vol. 117, Iss. 13 — 23 September 2016

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