Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 48: Poster: 2D Materials beyond Graphene: TMDCs, Silicene and Relatives
O 48.15: Poster
Dienstag, 13. März 2018, 18:15–20:30, Poster A
Intra- and inter-layer magnetic interactions in a van der Waals crystal — •Moemi Kawashima1,2, Akira Akaishi2, and Jun Nakamura2 — 1Department of Engineering Science, The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan — 2Institute of Condensed Matter Theory and Optics, Jena, Germany
Chromium triiodide (CrI3) with a layered structure is known to be a soft ferromagnet in its bulk form. Huang et al. recently reported that the magnetic properties of CrI3 differ when the layers approach the 2D limit, and become sensitive to the number of layers: monolayered and trilayered CrI3 are ferromagnetic, whereas bilayered CrI3 happens to be antiferromagnetic. In order to explore the mechanism of such a layer-number dependent magnetism of CrI3, we have investigated the magnetic properties of CrI3 thin films using the van der Waals density functional theory. We have found out that the ground states for all of monolayered, bilayered and trilayered CrI3 are ferromagnetic, in both the low-temperature (R3 with an ABC-stacking) and high-temperature (C2/m with another ABC-stacking) structure. However, it has been revealed that trilayered CrI3 is most stable with an AA-stacked structure, and the magnetic ground state of bilayered CrI3 becomes antiferromagnetic with an AA-stacked structure. These results suggest that the bilayered CrI3 observed in the experiments of Huang et al. had an AA-stacked structure, and that the crystallographic properties of 2D CrI3 have a strong connection to its magnetism. We will also discuss impacts of the choice of the van der Waals functional on the magnetic interaction through van der Waals interactions.