Symmetry-protected hierarchy of anomalous multipole topological band gaps in nonsymmorphic metacrystals.

ABSTRACT: Symmetry and topology are two fundamental aspects of many quantum states of matter. Recently new topological materials, higher-order topological insulators, were discovered, featuring bulk-edge-corner correspondence that goes beyond the conventional topological paradigms. Here we discover experimentally that the nonsymmorphic p4g acoustic metacrystals host a symmetry-protected hierarchy of topological multipoles: the lowest band gap has a quantized Wannier dipole and can mimic the quantum spin Hall effect, whereas the second band gap exhibits quadrupole topology with anomalous Wannier bands. Such a topological hierarchy allows us to observe experimentally distinct, multiplexed topological phenomena and to reveal a topological transition triggered by the geometry transition from the p4g gro

SUBMITTER: Zhang X 

PROVIDER: S-EPMC6941978 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature