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arXiv · 2503.03700

Real-Space Switching of Local Moments Driven by Quantum Geometry in Correlated Graphene Heterostructures

Niklas Witt·Siheon Ryee·Lennart Klebl·Jennifer Cano·Giorgio Sangiovanni·Tim O. Wehling
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Abstract

Graphene-based multilayer systems serve as versatile platforms for exploring the interplay between electron correlation and topology, thanks to distinctive low-energy bands marked by significant quantum metric and Berry curvature from graphene's Dirac bands. Here, we investigate Mott physics and local spin moments in Dirac bands hybridized with a flat band of localized orbitals in functionalized graphene. Via hybridization control, a topological transition is realized between two symmetry-distinct site-selective Mott states featuring local moments in different Wyckoff positions, with a geometrically enforced metallic state emerging in between. We find that this geometrically controlled real-space switching of local moments and associated metal-insulator physics may be realized through proximity coupling of epitaxial graphene on SiC(0001) with group IV intercalants, where the Mott state faces geometrical obstruction in the large-hybridization limit. Our work shows that chemically functionalized graphene provides a correlated electron platform, very similar to the topological heavy fermions in graphene moir\'e systems but at significantly enhanced characteristic energy scales.

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Niklas Witt, Siheon Ryee, Lennart Klebl, Jennifer Cano, Giorgio Sangiovanni, Tim O. Wehling. 2025-03-05. Real-Space Switching of Local Moments Driven by Quantum Geometry in Correlated Graphene Heterostructures. https://doi.org/10.1103/xnr5-4h6m

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