G54: Magnetic 2D van der Waals Materials

Tue. March 15, 11:30 a.m. – 2:30 p.m. CDT

Room: McCormick Place W-476

Sponsoring Units: GMAGChair: Dustin Gilbert, University of Tennessee: Knoxville
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Tue. March 15, 11:30 a.m. – 11:42 a.m. CDT

McCormick Place W-476

Presenter: Jesse Kapeghian (Arizona State University)
Authors: Jesse Kapeghian (Arizona State University), Muhammad Akram (Arizona State University), Harrison LaBollita (Arizona State University), Dibyendu Dey (University of Maine), Onur Erten (Arizona State University), Antia S Botana (Argonne National Laboratory)

We present a comprehensive theory of the magnetic phases in twisted bilayer chromium trihalides through first-principles calculations and atomistic simulations [1]. In this talk, the first-principles simulations will be described. Our calculations permit to build an effective spin model for the bilayers with the isotropic and anisotropic Cr-Cr exchange couplings, the single ion anisotropy, and the interlayer exchange coupling. The intralayer Heisenberg exchange coupling is found to be ferromagnetic and with a value that decreases from I to Cl, as expected. The correct (experimental) magnetic anisotropy (out-of-plane for CrI3 and CrBr3 and in-plane for CrCl3) is also reproduced. More importantly, we find that the stacking-dependent interlayer exchange leads to an effective moiré field that is mostly ferromagnetic with antiferromagnetic patches in all three materials. As such, the competing stacking-dependent interlayer interactions can give rise to novel magnetic states upon twisting.

[1] Muhammad Akram, Harrison LaBollita, Dibyendu Dey, Jesse Kapeghian, Onur Erten, and Antia S. Botana Nano Letters 2021 21 (15), 6633-6639