High spin axion insulator
| Autor: | Li, Shuai, Gong, Ming, Li, Yu-Hang, Jiang, Hua, Xie, X. C. |
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| Rok vydání: | 2024 |
| Předmět: | |
| Zdroj: | Nat Commun 15, 4250 (2024) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1038/s41467-024-48542-4 |
| Popis: | Axion insulators possess a quantized axion field $\theta=\pi$ protected by combined lattice and time-reversal symmetry, holding great potential for device applications in layertronics and quantum computing. Here, we propose a high-spin axion insulator (HSAI) defined in large spin-$s$ representation, which maintains the same inherent symmetry but possesses a notable axion field $\theta=(s+1/2)^2\pi$. Such distinct axion field is confirmed independently by the direct calculation of the axion term using hybrid Wannier functions, layer-resolved Chern numbers, as well as the topological magneto-electric effect. We show that the guaranteed gapless quasi-particle excitation is absent at the boundary of the HSAI despite its integer surface Chern number, hinting an unusual quantum anomaly violating the conventional bulk-boundary correspondence. Furthermore, we ascertain that the axion field $\theta$ can be precisely tuned through an external magnetic field, enabling the manipulation of bonded transport properties. The HSAI proposed here can be experimentally verified in ultra-cold atoms by the quantized non-reciprocal conductance or topological magnetoelectric response. Our work enriches the understanding of axion insulators in condensed matter physics, paving the way for future device applications. Comment: To appear in Nature Communications |
| Databáze: | arXiv |
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