English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Topological crystalline insulators (TCIs) can exhibit unique, quantizedelectric phenomena such as fractional electric polarization andboundary-localized fractional charge. This quantized fractional charge is thegeneric observable for identification of TCIs that lack robust spectralfeatures, including ones having higher-order topology. It has been predictedthat fractional charges can also manifest where crystallographic defectsdisrupt the lattice structure of TCIs, potentially providing a bulk probe ofcrystalline topology. However, this capability has not yet been confirmed inexperiment since measurements of charge distributions in TCIs have not beenaccessible until recently. Here, we experimentally demonstrate thatdisclination defects can robustly trap fractional charges in TCI metamaterials,and show that this trapped charge can indicate non-trivial higher-ordercrystalline topology even in the absence of any spectral signatures.Furthermore, we uncover a connection between the trapped charge and theexistence of topological bound states localized at these defects. We test therobustness of these topological features when the protective crystallinesymmetry is broken, and find that a single robust bound state can be localizedat each disclination alongside the fractional charge. Our results conclusivelyshow that disclination defects in TCIs can robustly trap fractional charges aswell as topological bound states, and moreover demonstrate the primacy offractional charge as a probe of crystalline topology.

Observation of trapped fractional charge and topological states at disclination defects in higher-order topological insulators