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arXiv · 2310.10779

Fragile dislocation modes in obstructed atomic topological phases

Gabriel Malavé·Jorge Schifferli·Rodrigo Soto-Garrido·Pedro A. Orellana·Vladimir Juričić
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Abstract

We here introduce the concept of fragile topological dislocation modes, which are localized only in a fraction of a topological phase, while otherwise leak into the bulk continuum. We show that such dislocation modes are hosted in an obstructed atomic topological phase in the two-dimensional Su-Schrieffer-Heeger model, but only in a finite region with an indirect gap at high energy. These dislocation modes are realized as chiral pairs at finite energies with protection stemming from a combination of the chiral (unitary particle-hole) and the point group (C$_{4v}$) symmetries, but only when the indirect gap is open. In this regime, we corroborate the stability of the defect modes by following their localization and also by explicitly adding a weak chemical potential disorder. Our findings, therefore, should be consequential for the experimental observation of such modes in designer topological crystals and classical metamaterials.

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Gabriel Malavé, Jorge Schifferli, Rodrigo Soto-Garrido, Pedro A. Orellana, Vladimir Juričić. 2023-10-16. Fragile dislocation modes in obstructed atomic topological phases. https://doi.org/10.1103/physrevb.109.l201407

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