Intercalation of magnetic atoms into van der Waals materials provides a versatile platform for tailoring unconventional magnetic properties. However, its impact on electronic dimensionality and exchange mechanisms remains poorly understood. Using Fe-intercalated TaS2 as a model system, we combine X-ray absorption and resonant inelastic scattering with angle-resolved photoemission and first-principles calculations to reveal that intercalation reshapes the host electronic structure. We identify a spin-polarized intercalant-host hybridized band with pronounced out-of-plane dispersion crossing the Fermi level, providing an itinerant channel for interlayer magnetic exchange. This mechanism explains the breakdown of a purely atomic picture and establishes a direct link between lattice geometry, electronic dispersion, and magnetic order. Our findings demonstrate that intercalant-induced itinerancy enables tunable interlayer coupling in otherwise layered magnets, offering a general microscopic framework for engineering magnetic dimensionality in a broad class of intercalated vdW materials.
@article{arxiv.2602.03457,
title = {Emergent 3D Fermiology and Magnetism in an Intercalated Van der Waals System},
author = {Luigi Camerano and Emanuel A. Martínez and Victor Porée and Laura Martella and Dario Mastrippolito and Debora Pierucci and Franco D'Orazio and Polina M. Sheverdyaeva and Paolo Moras and Enrico Della Valle and Tianlun Yu and Moritz Hoesch and Craig M. Polley and Thiagarajan Balasubramanian and Alessandro Nicolaou and Luca Ottaviano and Vladimir N. Strocov and Gianni Profeta and Federico Bisti},
journal= {arXiv preprint arXiv:2602.03457},
year = {2026}
}