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arXiv · 2008.04719

Acoustic square-root topological insulators

Mou Yan·Xueqin Huang·Li Luo·Jiuyang Lu·Weiyin Deng·Zhengyou Liu
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Abstract

Square-root topological states are new topological phases, whose topological property is inherited from the square of the Hamiltonian. We realize the first-order and second-order square-root topological insulators in phononic crystals, by putting additional cavities on connecting tubes in the acoustic Su-Schrieffer-Heeger model and the honeycomb lattice, respectively. Because of the square-root procedure, the bulk gap of the squared Hamiltonian is doubled. In both two bulk gaps, the square-root topological insulators possess multiple localized modes, i.e., the end and corner states, which are evidently confirmed by our calculations and experimental observations. We further propose a second-order square-root topological semimetal by stacking the decorated honeycomb lattice to three dimensions.

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Mou Yan, Xueqin Huang, Li Luo, Jiuyang Lu, Weiyin Deng, Zhengyou Liu. 2020-08-11. Acoustic square-root topological insulators. https://doi.org/10.1103/physrevb.102.180102

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