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Article Dans Une Revue Nature Communications Année : 2024

Observation of Kekulé vortices around hydrogen adatoms in graphene

Résumé

Abstract Fractional charges are one of the wonders of the fractional quantum Hall effect. Such objects are also anticipated in two-dimensional hexagonal lattices under time reversal symmetry—emerging as bound states of a rotating bond texture called a Kekulé vortex. However, the physical mechanisms inducing such topological defects remain elusive, preventing experimental realization. Here, we report the observation of Kekulé vortices in the local density of states of graphene under time reversal symmetry. The vortices result from intervalley scattering on chemisorbed hydrogen adatoms. We uncover that their 2 π winding is reminiscent of the Berry phase π of the massless Dirac electrons. We can also induce a Kekulé pattern without vortices by creating point scatterers such as divacancies, which break different point symmetries. Our local-probe study thus confirms point defects as versatile building blocks for Kekulé engineering of graphene’s electronic structure.

Dates et versions

hal-04535698 , version 1 (07-04-2024)

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Citer

Yifei Guan, Clement Dutreix, Héctor González-Herrero, Miguel Ugeda, Ivan Brihuega, et al.. Observation of Kekulé vortices around hydrogen adatoms in graphene. Nature Communications, 2024, 15 (1), pp.2927. ⟨10.1038/s41467-024-47267-8⟩. ⟨hal-04535698⟩
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