Dresden 2026 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 7: Poster Magnetism I
MA 7.47: Poster
Montag, 9. März 2026, 09:30–12:30, P2
X-ray Absorption Spectroscopy and X-ray Magnetic Circular Dichroism investigation of magnetic properties in monolayer van-der-Waals 3d transition metal diiodides — •Lorenzo Grilli1, Amina Kimouche2, Awsaf Chowdhury1, Jendrik Gördes1, Chen Luo3, Florin Radu3, Sangeeta Thakur1, Marcel Walter1, and Wolfgang Kuch1 — 1Freie Universität Berlin, Germany — 2Universität Potsdam, Germany — 3Helmholtz-Zentrum Berlin for Materials and Energy, Germany
Numerous theoretical works [e.g. A. S. Botana, Phys. Rev. Materials 3, 044001 (2019)] predict that robust magnetic order can persist down to the monolayer limit in 3d transition-metal dihalides. Here we investigate the epitaxial growth and electronic properties of ultrathin MnI2 and CoI2 films on heavy-metal and van-der-Waals substrates, using thermal evaporation from stoichiometric sources. Structural properties are characterized in-situ by LEED and XPS. Motivated by STM results [Daniel Rothhardt et al., ACS Nano 19, 2261 (2025)] showing that iodine reacts with Ag before forming MnI2 islands, we use XPS to quantify stoichiometry and interface chemistry for MnI2 grown on Ag(111) and on graphene, directly comparing a reactive metal substrate with an inert van-der-Waals one. In parallel, we explore growth of CoI2 on similar substrates. The magnetic response of these epitaxial films is probed by XAS and XMCD at the VEKMAG end station of BESSY II, providing element-specific sensitivity to spin and orbital moments in the ultrathin limit. We discuss how the substrate influences the magnetic behaviour of MnI2 and CoI2 monolayers.
Keywords: X-ray spectroscopy; Van-der-Waals materials; Two-dimensional magnetism; Epitaxy