Broken-helix antiferromagnetic order protecting a crystalline axion insulator phase and exotic surface states in EuIn<sub>2</sub>As<sub>2</sub>

ORAL

Abstract

EuIn2As2 is theoretically predicted to order in a collinear antiferromagnetic structure that preserves inversion symmetry and induces an axion-insulator state. Combining results from neutron diffraction, symmetry analyses and density functional theory, we show that EuIn2As2 instead exhibits low-symmetry helical antiferromagnetic order which breaks inversion. However, the combination of a 180° rotation and time-reversal symmetry (C2 x T= 2’) elements still makes the compound a stoichiometric magnetic topological-crystalline axion insulator. Surfaces normal to the 2' symmetry axes show exotic gapless Dirac cones (DC) which are unpinned to specific time-reversal invariant momenta (TRIM). Gapped DC pinned to TRIM appear on the other surfaces. Dissipationless charge transport arises on the 2' protected surfaces while half-integer quantum anomalous-type conductivity occurs on the other surfaces. We predict that modest values of applied magnetic field can switch between the different surfaces states.

*This work was supported by the Center for Advancement of Topological Semimetals, an Energy Frontier Research Center funded by the U.S. DOE Office of Science, Office of BES, through Ames Laboratory under its Contract No. DE-AC02-07CH11358.

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Presenters

  • Simon Riberolles

    • Physics and Astronomy, Iowa State University/Ames Laboratory
    • Division of Materials Science & Engineering, Ames Laboratory
    • Ames Laboratory and Iowa State Univeristy

Authors

  • Simon Riberolles

    • Physics and Astronomy, Iowa State University/Ames Laboratory
    • Division of Materials Science & Engineering, Ames Laboratory
    • Ames Laboratory and Iowa State Univeristy

  • Thais Victa Trevisan

    • Department of Physics and Astronomy, Ames Laboratory, Iowa State University

  • Brinda Kuthanazhi

    • Department of Physics and Astronomy, Ames Laboratory, Iowa State University
    • Ames Laboratory, Iowa State University
    • Department of Physics and Astronomy, Iowa State University/Ames Laboratory
    • Department of Physics & Astronomy, Iowa State University/Ames Laboratory
    • Ames Laboratory/Iowa State University

  • Thomas W Heitmann

    • University of Missouri
    • University of Missouri Research Reactor
    • The Missouri Research Reactor, University of Missouri, Columbia, Missouri
    • Missouri Research Reactor, University of Missouri
    • University of Missouri Research Reactor, University of Missouri

  • Feng Ye

    • Oak Ridge National Laboratory
    • Oak Ridge National Lab
    • Neutron Scattering Division, Oak Ridge National Laboratory

  • David C Johnston

    • Department of Physics and Astronomy, Ames Laboratory, Iowa State University
    • Ames Laboratory and Iowa State University, Ames, IA USA 50011

  • Sergey L. Bud'ko

    • Department of Physics and Astronomy, Ames Laboratory, Iowa State University
    • Ames Laboratory, Iowa State University
    • Ames Laboratory, Iowa State University, Dept. of Physics and Astronomy, Ames
    • Ames Laboratory, U.S. Department of Energy, and Department of Physics and Astronomy, Iowa State University
    • Ames Laboratory/Iowa State University

  • Dominic H Ryan

    • Physics, McGill University
    • Physics Department and Centre for the Physics of Materials, McGill University
    • McGill University

  • Paul C. Canfield

    • Ames Laboratory/Iowa State University
    • Department of Physics and Astronomy, Ames Laboratory, Iowa State University
    • Ames Laboratory, Iowa State University, Dept. of Physics and Astronomy, Ames
    • Ames Laboratory, U.S. Department of Energy; Department of Physics, Iowa State University

  • Andreas Kreyssig

    • Physics and Astronomy, Iowa State University/Ames Laboratory
    • Department of Physics and Astronomy, Ames Laboratory, Iowa State University
    • Ames Lab/Iowa State
    • Ames Laboratory, Iowa State University, Dept. of Physics and Astronomy, Ames
    • Ames Laboratory and Iowa State Univeristy

  • Ashvin Vishwanath

    • Harvard University
    • Department of Physics, Harvard University
    • Department of Physics and Astronomy, Harvard University
    • Department of Physics, Harvard university

  • Robert J McQueeney

    • Ames Lab
    • Physics and Astronomy, Iowa State University/Ames Laboratory
    • Department of Physics and Astronomy, Ames Laboratory, Iowa State University
    • Ames Lab/Iowa State
    • Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, USA
    • Iowa State University
    • Ames Laboratory and Iowa State University, Ames, IA USA 50011
    • Ames Laboratory/Iowa State University

  • Lin-Lin Wang

    • Ames Laboratory
    • Ames Laboratory/Iowa State University
    • Department of Physics and Astronomy, Ames Laboratory, Iowa State University
    • Department of Physics and Astronomy, Iowa State University/Ames Laboratory

  • Peter Orth

    • Department of Physics and Astronomy, Ames Laboratory, Iowa State University
    • Iowa State University
    • Department of Physics and Astronomy, Iowa State University/Ames Laboratory
    • Ames Laboratory, Iowa State University

  • Benjamin Ueland

    • Ames Lab
    • Physics and Astronomy, Iowa State University/Ames Laboratory
    • Division of Materials Science & Engineering, Ames Laboratory
    • Ames Laboratory and Iowa State University, Ames, IA USA 50011
    • Ames Laboratory/Iowa State University