Time-periodic corner states from Floquet higher-order topology
The recent discoveries of higher-order topological insulators (HOTIs) have shifted the paradigm of topological materials, previously limited to topological states at boundaries of materials, to include topological states at boundaries of boundaries, such as corners. So far, all HOTI realisations hav...
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sg-ntu-dr.10356-1551422023-02-28T19:21:26Z Time-periodic corner states from Floquet higher-order topology Zhu, Weiwei Xue, Haoran Gong, Jiangbin Chong, Yidong Zhang, Baile School of Physical and Mathematical Sciences Centre for Disruptive Photonic Technologies (CDPT) Science::Physics Topological Insulator The recent discoveries of higher-order topological insulators (HOTIs) have shifted the paradigm of topological materials, previously limited to topological states at boundaries of materials, to include topological states at boundaries of boundaries, such as corners. So far, all HOTI realisations have been based on static systems described by time-invariant Hamiltonians, without considering the time-variant situation. There is growing interest in Floquet systems, in which time-periodic driving can induce unconventional phenomena such as Floquet topological phases and time crystals. Recent theories have attempted to combine Floquet engineering and HOTIs, but there has been no experimental realisation so far. Here we report on the experimental demonstration of a two-dimensional (2D) Floquet HOTI in a three-dimensional (3D) acoustic lattice, with modulation along a spatial axis serving as an effective time-dependent drive. Acoustic measurements reveal Floquet corner states with double the period of the underlying drive; these oscillations are robust, like time crystal modes, except that the robustness arises from topological protection. This shows that space-time dynamics can induce anomalous higher-order topological phases unique to Floquet systems. Ministry of Education (MOE) National Research Foundation (NRF) Published version B.Z. and Y.C. acknowledge funding support by the Singapore Ministry of Education Academic Research Fund Tier-3 (Grant No. MOE2016-T3-1-006) and Tier 2 (Grant No. MOE2019-T2-2-085). J.G. acknowledges funding support by the Singapore Ministry of Education Academic Research Fund Tier-3 Grant No. MOE2017-T3-1-001 (WBS No. R144-000-425-592) and by the Singapore NRF Grant No. NRF-NRFI2017-04 (WBS No. R-144-000-378- 281). 2022-02-11T02:47:54Z 2022-02-11T02:47:54Z 2022 Journal Article Zhu, W., Xue, H., Gong, J., Chong, Y. & Zhang, B. (2022). Time-periodic corner states from Floquet higher-order topology. Nature Communications, 13(1), 11-. https://dx.doi.org/10.1038/s41467-021-27552-6 2041-1723 https://hdl.handle.net/10356/155142 10.1038/s41467-021-27552-6 35013180 2-s2.0-85122864607 1 13 11 en Nature Communications 10.21979/N9/YBSECE © 2022 The Author(s). This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/ licenses/by/4.0/. application/pdf |
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The recent discoveries of higher-order topological insulators (HOTIs) have shifted the paradigm of topological materials, previously limited to topological states at boundaries of materials, to include topological states at boundaries of boundaries, such as corners. So far, all HOTI realisations have been based on static systems described by time-invariant Hamiltonians, without considering the time-variant situation. There is growing interest in Floquet systems, in which time-periodic driving can induce unconventional phenomena such as Floquet topological phases and time crystals. Recent theories have attempted to combine Floquet engineering and HOTIs, but there has been no experimental realisation so far. Here we report on the experimental demonstration of a two-dimensional (2D) Floquet HOTI in a three-dimensional (3D) acoustic lattice, with modulation along a spatial axis serving as an effective time-dependent drive. Acoustic measurements reveal Floquet corner states with double the period of the underlying drive; these oscillations are robust, like time crystal modes, except that the robustness arises from topological protection. This shows that space-time dynamics can induce anomalous higher-order topological phases unique to Floquet systems. |
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School of Physical and Mathematical Sciences |
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School of Physical and Mathematical Sciences Zhu, Weiwei Xue, Haoran Gong, Jiangbin Chong, Yidong Zhang, Baile |
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Article |
author |
Zhu, Weiwei Xue, Haoran Gong, Jiangbin Chong, Yidong Zhang, Baile |
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Zhu, Weiwei |
title |
Time-periodic corner states from Floquet higher-order topology |
title_short |
Time-periodic corner states from Floquet higher-order topology |
title_full |
Time-periodic corner states from Floquet higher-order topology |
title_fullStr |
Time-periodic corner states from Floquet higher-order topology |
title_full_unstemmed |
Time-periodic corner states from Floquet higher-order topology |
title_sort |
time-periodic corner states from floquet higher-order topology |
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2022 |
url |
https://hdl.handle.net/10356/155142 |
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1759855288031117312 |