Experimental realization of the minimal two-dimensional multi-orbital kagome model

Bing Liu; Arka Bandyopadhyay; Manish Verma; Jonas Erhardt; Tim Wagner; Jing Qi; Kilian Strauß; Domenico Di Sante; Carmine Ortix; Simon Moser; Jörg Schäfer; Ronny Thomale; Giorgio Sangiovanni; Ralph Claessen

arXiv · 2609.31063

Experimental realization of the minimal two-dimensional multi-orbital kagome model

Bing Liu·Arka Bandyopadhyay·Manish Verma·Jonas Erhardt·Tim Wagner·Jing Qi·Kilian Strauß·Domenico Di Sante·Carmine Ortix·Simon Moser·Jörg Schäfer·Ronny Thomale·Giorgio Sangiovanni·Ralph Claessen

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Abstract

Kagome materials have emerged as a major platform for correlated and topological quantum matter, hosting flat bands, Dirac dispersions and van Hove singularities rooted in frustrated lattice geometry. While their essential physics is epitomized by the canonical single-orbital kagome model, real kagome materials are intrinsically multi-orbital and typically chemically and structurally complex, with additional three-dimensional coupling making kagome geometry and orbital degrees of freedom difficult to disentangle. Here we realize a truly two-dimensional, elemental two-orbital kagome system in monolayer Sb on SiC(0001). Substrate-induced orbital filtering isolates the in-plane Sb p_x/p_y orbitals into a six-band kagome manifold, establishing a chemically simple, minimal platform for multi-orbital kagome physics. We demonstrate two consequences that distinguish this system from the canonical single-orbital model. First, chemically enforced half filling pins the Fermi level to a closed nodal line, whose finite density of states drives a unit-cell-conserving breathing instability and opens a giant insulating gap. Second, we uncover orbital-resolved atomic obstruction: individual orbital-derived manifolds realize obstructed atomic limits, whereas their combined half-filled valence manifold is non-obstructed. Our results establish kagome antimonene as a benchmark system for exploring orbital-driven electronic, structural and topological kagome physics in the genuine two-dimensional limit.

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Bing Liu, Arka Bandyopadhyay, Manish Verma, Jonas Erhardt, Tim Wagner, Jing Qi, Kilian Strauß, Domenico Di Sante, Carmine Ortix, Simon Moser, Jörg Schäfer, Ronny Thomale, Giorgio Sangiovanni, Ralph Claessen. 2026-09-25. Experimental realization of the minimal two-dimensional multi-orbital kagome model. https://arxiv.org/abs/2609.31063

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