Fractional corner charges in threefold-symmetric two-dimensional materials with fragile topology

2023/12/14 by Olga Arroyo-Gascón, Arroyo-Gascón, Olga, Sergio Bravo +5
Materials Science · Physics and Astronomy · #2D Materials and Applications #FOS: Physical sciences #Graphene research and applications #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Topological Materials and Phenomena

paper · pdf · doi:10.48550/arxiv.2312.09240

openalex publication_date 2023/12/14 · openalex created_date 2023/12/16 · openalex updated_date 2026/08/01

Abstract

We perform a systematic study of the signatures of fragile topology in over 50 nonmagnetic two-dimensional materials with formula AB₂, belonging to space group P-3m1. Using group theory analysis in the framework of topological quantum chemistry, we find fragile bands near the Fermi level for all the materials studied. Since stable topological bands are also present in these systems, the interplay of both phases is discussed, showing that corner charges appear in over 80% of the materials and are linked to fragile topology. Using first-principles calculations, we predict fractionally-charged corner charges protected by C₃ symmetry. Our work aims to broaden the scope of materials with experimentally accessible fragile bands.

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