Magnetic crystalline-symmetry-protected axion electrodynamics and field-tunable unpinned Dirac cones in EuIn2As2
| Autor: | Riberolles, S. X. M., Trevisan, T. V., Kuthanazhi, B., Heitmann, T. W., Ye, F., Johnston, D. C., Bud'ko, S. L., Ryan, D. H., Canfield, P. C., Kreyssig, A., Vishwanath, A., McQueeney, R. J., Wang, L. -L., Orth, P. P., Ueland, B. G. |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Nature Communications volume 12, Article number: 999 (2021) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1038/s41467-021-21154-y |
| Popis: | Knowledge of magnetic symmetry is vital for exploiting nontrivial surface states of magnetic topological materials. EuIn$_{2}$As$_{2}$ 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 EuIn$_{2}$As$_{2}$ actually exhibits low-symmetry helical antiferromagnetic order which makes it a stoichiometric magnetic topological-crystalline axion insulator protected by the combination of a 180$^{\circ}$ rotation and time-reversal symmetries: $C_{2}\times\mathcal{T}=2^{\prime}$. Surfaces protected by $2^{\prime}$ 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 $H\approx1$ to $2$ T can tune between gapless and gapped surface states. Comment: 49 pages, 26 figures |
| Databáze: | arXiv |
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