Emergent 3D Fermiology and Magnetism in an Intercalated Van der Waals System

TL;DR

This study reveals how intercalating magnetic atoms into van der Waals materials modifies their electronic structure and magnetic interactions, enabling tunable interlayer magnetic coupling through emergent itinerant electronic states.

Contribution

It introduces a comprehensive experimental and theoretical framework showing how intercalation induces itinerant electronic states that control magnetic coupling in layered vdW materials.

Findings

Intercalation reshapes the electronic structure of the host material.

A spin-polarized hybridized band with out-of-plane dispersion crosses the Fermi level.

Intercalant-induced itinerancy enables tunable interlayer magnetic coupling.

Abstract

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 TaS$_2$ 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.