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arXiv · 2303.14794

Anomalous open orbits in Hofstadter spectrum of Chern insulator

Haijiao Ji·Noah F. Q. Yuan·Hua Jiang·Haiwen Liu·X. C. Xie
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Abstract

The nontrivial band topology can influence the Hofstadter spectrum. We investigate the Hofstadter spectrum for various models of Chern insulators under a rational flux $\frac{\phi_{0}}{q}$, here $\phi_{0}=\frac{h}{e}$ and $q$ being an integer. We find two major features. First, the number of splitting subbands is $|q-C|$ with Chern number $C$. Second, the anomalous open-orbit subbands with Chern numbers $q-1$ and $-q-1$ emerge, which are beyond the parameter window $(-q/2,q/2)$ of the Diophantine equation studied by Thouless-Kohmoto-Nightingale-den Nijs [Phys. Rev. Lett. \textbf{49}, 405 (1982)]. These two findings are explained by semiclassical dynamics. We propose that the number of splitting subbands can be utilized to determine Chern number in cold atom systems, and the open-orbit subbands can provide routes to study exotic features beyond the Landau level physics.

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Haijiao Ji, Noah F. Q. Yuan, Hua Jiang, Haiwen Liu, X. C. Xie. 2023-03-26. Anomalous open orbits in Hofstadter spectrum of Chern insulator. https://arxiv.org/abs/2303.14794

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