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

We perform a systematic study of the signatures of fragile topology in over 50 nonmagnetic two-dimensional materials with formula AB_{2}, belonging to space group P3[over ¯]m1. Using group theory analysis in the framework of topological quantum chemistry, we find fragile bands near the Fermi level f...

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Bibliographic Details
Main Authors: Olga Arroyo-Gascón, Sergio Bravo, Leonor Chico, Mónica Pacheco
Format: Article
Language:English
Published: American Physical Society 2025-06-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/qcr8-jxvn
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Summary:We perform a systematic study of the signatures of fragile topology in over 50 nonmagnetic two-dimensional materials with formula AB_{2}, belonging to space group P3[over ¯]m1. 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 C_{3} symmetry. Our work aims to broaden the scope of materials with experimentally accessible fragile bands.
ISSN:2643-1564