SKM 2021 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 4: Focus Session: Correlated van-der-Waals Magnets
TT 4.5: Vortrag
Montag, 27. September 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.