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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.

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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