SKM 2021 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 4: Focus Session: Correlated van-der-Waals Magnets

TT 4.5: Talk

Monday, September 27, 2021, 15:15–15:30, H7

Coulomb-Engineered Magnetism in CrI₃ Monolayer — David Soriano, Alexander Rudenko, Mikhail Katsnelson, and •Malte Rösner — Radboud University, Nijmegen, Netherlands

We present a detailed study on the microscopic origin of magnetism in suspended and dielectrically embedded CrI₃ monolayer. To this end, we down-fold minimal generalized Hubbard models from ab initio calculations using the constrained random phase approximation. Within mean-field approximation, we show that these models are capable of describing the formation of localized magnetic moments in CrI₃ and of reproducing electronic properties of full ab initio calculations. We find a multi-orbital super-exchange mechanism as the origin of magnetism in CrI₃ resulting from a detailed interplay between effective ferro- and anti-ferromagnetic Cr-Cr d coupling channels, which is decisively affected by the ligand (I) p orbitals. We show how environmental screening such as resulting from encapsulation with hexagonal boron nitride (hBN) of the CrI₃ monolayer affects the Coulomb interaction in the film and how this successively controls its magnetic properties. Driven by a non-monotonic interplay between nearest and next-nearest neighbour exchange interactions we find the magnon dispersion and the Curie temperature to be non-trivially affected by the environmental dielectric screening.