Jiang Tianshu, Zhang Chenyu, Zhang Ruo-Yang, Yu Yingjuan, Guan Zhenfu, Wei Zeyong, Wang Zhanshan, Cheng Xinbin, Chan C T
MOE Key Laboratory of Advanced Micro-Structured Materials, Shanghai Frontiers Science Center of Digital Optics, Institute of Precision Optical Engineering, and School of Physics Science and Engineering, Tongji University, Shanghai, 200092, China.
Department of Physics, The Hong Kong University of Science and Technology, Hong Kong, China.
Nat Commun. 2024 Dec 30;15(1):10863. doi: 10.1038/s41467-024-55218-6.
The hybrid skin-topological effect (HSTE) has recently been proposed as a mechanism where topological edge states collapse into corner states under the influence of the non-Hermitian skin effect (NHSE). However, directly observing this effect is challenging due to the complex frequencies of eigenmodes. In this study, we experimentally observe HSTE corner states using synthetic complex frequency excitations in a transmission line network. We demonstrate that HSTE induces asymmetric transmission along a specific direction within the topological band gap. Besides HSTE, we identify corner states originating from non-chiral edge states, which are caused by the unbalanced effective onsite energy shifts at the boundaries of the network. Furthermore, our results suggest that whether the bulk interior is Hermitian or non-Hermitian is not a key factor for HSTE. Instead, the HSTE states can be realized and relocated simply by adjusting the non-Hermitian distribution at the boundaries. Our research has deepened the understanding of a range of issues regarding HSTE, paving the way for advancements in the design of non-Hermitian topological devices.
混合皮肤拓扑效应（HSTE）最近被提出作为一种机制，即在非厄米皮肤效应（NHSE）的影响下，拓扑边缘态坍缩为角态。然而，由于本征模的频率复杂，直接观察这种效应具有挑战性。在本研究中，我们在传输线网络中使用合成复频率激励，通过实验观察到了HSTE角态。我们证明，HSTE会在拓扑带隙内沿特定方向诱导不对称传输。除了HSTE，我们还识别出了源自非手性边缘态的角态，这是由网络边界处有效在位能移不平衡引起的。此外，我们的结果表明，主体内部是厄米的还是非厄米的并非HSTE的关键因素。相反，只需调整边界处的非厄米分布，就能实现并重新定位HSTE态。我们的研究加深了对一系列关于HSTE问题的理解，为非厄米拓扑器件的设计进展铺平了道路。
