Symmetry-Related Large-Area Corner Mode with a Tunable Mode Area and Stable Frequency
Zhongfu Li, Shiqi Li, Bei Yan, Hsun‐Chi Chan, Jing Li, Jun Guan, Wengang Bi, Yuanjiang Xiang, Z. Gao, Shuang Zhang, Peng Zhan, Zhenlin Wang, Biye Xie
Abstract
Emergent collective modes in lattices give birth to many intriguing physical phenomena in condensed matter physics. Among these collective modes, large-area modes typically feature small-level spacings, while a mode with stable frequency tends to be spatially tightly confined. In this Letter, we theoretically propose and experimentally demonstrate a symmetry-related large-area topological corner mode with a tunable mode area and stable frequency. This mode emerges from the hybridization of the homogeneous Dirac point mode and in-gap topological corner modes. Remarkably, this hybridized mode possesses unique chirality related to the chiral symmetry. We experimentally observe such hybridized mode in a two-dimensional (2D) photonic system and demonstrate its robustness by introducing disorders in the structure. Our findings advance the frontier of higher-order topology research, transitioning it from single-lattice systems to hybridized multilattice systems. These results may support promising potential applications, particularly in vertical-cavity surface-emitting lasers.