Campus Units

Physics and Astronomy, Ames Laboratory

Document Type

Article

Publication Version

Submitted Manuscript

Publication Date

2020

Journal or Book Title

arXiv

Abstract

Knowledge of magnetic symmetry is vital for exploiting nontrivial surface states of magnetic topological materials. EuIn2As2 is an excellent example, as it is predicted to have collinear antiferromagnetic order where the magnetic moment direction determines either a topological-crystalline-insulator phase supporting axion electrodynamics or a higher-order-topological-insulator phase with chiral hinge states. Here, we use neutron diffraction, symmetry analysis, and density functional theory results to demonstrate that EuIn2As2 actually exhibits low-symmetry helical antiferromagnetic order which makes it a stoichiometric magnetic topological-crystalline axion insulator protected by the combination of a 180∘ rotation and time-reversal symmetries: C2×T=2′. Surfaces protected by 2′ are expected to have an exotic gapless Dirac cone which is unpinned to specific crystal momenta. All other surfaces have gapped Dirac cones and exhibit half-integer quantum anomalous Hall conductivity. We predict that the direction of a modest applied magnetic field of H≈1 to 2 T can tune between gapless and gapped surface states.

Comments

This is a pre-print of the article Riberolles, S. X. M., T. V. Trevisan, B. Kuthanazhi, T. W. Heitmann, F. Ye, D. C. Johnston, S. L. Bud'ko, D. H. Ryan, P. C. Canfield, A. Kreyssig, A. Vishwanath, R. J. McQueeney, L. L. Wang, P. P. Orth, and B. G. Ueland. "Magnetic crystalline-symmetry-protected axion electrodynamics and field-tunable unpinned Dirac cones in EuIn2As2" arXiv preprint arXiv:2007.12758 (2020). Posted with permission.

Copyright Owner

The Author(s)

Language

en

File Format

application/pdf

Published Version

Share

COinS