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arXiv · 1910.06868

Experimental characterization of fragile topology in an acoustic metamaterial

Valerio Peri·Zhi-Da Song·Marc Serra-Garcia·Pascal Engeler·Raquel Queiroz·Xueqin Huang·Weiyin Deng·Zhengyou Liu·B. Andrei Bernevig·Sebastian D. Huber
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Abstract

Symmetries crucially underlie the classification of topological phases of matter. Most materials, both natural as well as architectured, possess crystalline symmetries. Recent theoretical works unveiled that these crystalline symmetries can stabilize fragile Bloch bands that challenge our very notion of topology: while answering to the most basic definition of topology, one can trivialize these bands through the addition of trivial Bloch bands. Here, we fully characterize the symmetry properties of the response of an acoustic metamaterial to establish the fragile nature of the low-lying Bloch bands. Additionally, we present a spectral signature in the form of spectral flow under twisted boundary conditions.

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Valerio Peri, Zhi-Da Song, Marc Serra-Garcia, Pascal Engeler, Raquel Queiroz, Xueqin Huang, Weiyin Deng, Zhengyou Liu, B. Andrei Bernevig, Sebastian D. Huber. 2019-10-15. Experimental characterization of fragile topology in an acoustic metamaterial. https://doi.org/10.1126/science.aaz7654

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