Observation of hybrid-order topological pump in a Kekulé-textured graphene lattice
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Journal:
PHYSICAL REVIEW B
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Abstract:
The Thouless charge pumping protocol provides an effective route for realizing topological particle transport. To date, the first-order and higher-order topological pumps, exhibiting transitions of edge-bulk-edge and corner-bulk-corner states, respectively, are observed in a variety of experimental platforms. Here, we propose the concept of a hybrid-order topological pump that involves a transition of bulk, edge, and corner states simultaneously. More specifically, we consider a Kekulé-textured graphene lattice that features a tunable phase parameter. The finite sample of zigzag boundaries, where the corner configuration is abnormal and inaccessible by repeating unit cells, hosts topological responses at both the edges and corners. The former is protected by a nonzero winding number, while the latter can be explained by a nontrivial vector Chern number. Using our skillful acoustic experiments, we verify these nontrivial boundary landmarks and visualize the consequent hybrid-order topological pump process directly. This work deepens our understanding of higher-order topological phases and broadens the scope of topological pumps.
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Indexed by:
Journal paper
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Volume:
108
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Issue:
12
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Page Number:
125125
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Translation or Not:
no
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Date of Publication:
2023-09-18
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Links to published journals:
https://journals.aps.org/prb/abstract/10.1103/PhysRevB.108.125125