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00925njm 22002777a 4500 dc Arroyo Gascón, Olga author Bravo, Sergio author Pacheco, Mónica author Chico Gómez, Leonor María author 2025-08-07 Obstructed atomic phases, with their realizations in systems of diverse dimensionality, have recently arisen as one of the topological states with greatest potential to show higher-order phenomena. In this work we report a special type of obstruction, known as orbital-mediated atomic obstruction, in monolayers of materials with crystalline symmetry described by the space group P3m1. By means of a minimal tight-binding model and first-principles calculations, we show that this obstructed phase is related to the mismatch of the charge centers coming from the atomic limit with respect to the centers that are obtained from a reciprocal space description. Although we find atomic limits that correspond with occupied atomic sites, orbital-mediated atomic obstruction requires the presence of orbitals that have no support in real space. In order to demonstrate the nontrivial character of the obstruction, we confirm the presence of a filling anomaly for finite geometries that is directly associated with the bulk configuration, and discuss the role of the boundary states and their underlying mechanism. Several material examples are presented to illustrate the ubiquity of these nontrivial responses and, in turn, to discuss the differences related to the particular ground-state configuration. In addition, we perform a survey of materials and elaborate a list of candidate systems which will host this obstructed phase in monolayer form. O. Arroyo-Gascón, S. Bravo, M. Pacheco, and L. Chico, Two-dimensional orbital-obstructed insulators with higher-order band topology, Phys. Rev. B 112, 075114 (2025). 2469-9950 10.1103/gb96-1tqy https://hdl.handle.net/20.500.14352/126431 2469-9969 https://doi.org/10.1103/gb96-1tqy https://journals.aps.org/prb/abstract/10.1103/gb96-1tqy https://arxiv.org/abs/2412.09561 Two-dimensional orbital-obstructed insulators with higher-order band topology