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DS: Fachverband Dünne Schichten
DS 7: 2D Materials and their Heterostructures III
DS 7.5: Talk
Wednesday, March 20, 2024, 10:45–11:00, A 053
Nontrivial magnetic helical states and electric polarization in NiI2 monolayer — •Juraj Mnich1 and Martin Gmitra1,2 — 1Institute of Physics, Pavol Jozef Šafárik University in Košice, 04001 Košice, Slovakia — 2Institute of Experimental Physics, Slovak Academy of Sciences, 04001 Košice, Slovakia
A monolayer of NiI2 enriches a small group of 2D multiferroic materials possessing unique magnetic and electric polarization properties. Trigonal crystal symmetry and the interplay between spatially dependent ferromagnetic and antiferromagnetic exchange interactions, along with strong spin-orbit coupling, give rise to complex helical magnetic states. The helical state can be described by a wave propagation vector and a plane in which magnetic moments rotate. We studied several magnetic helical states using first-principles calculations. We found that the alignment of magnetic moments gives rise to unexpected electric polarization for a proper screw helical state. We also studied the interplay between the helical states and electric polarization in the NiI2 bilayer and we speculate that an in-plane bias voltage can induce rotation of the helical state via spin-transfer torque, dragging its phase and switching the wave propagation vector, reflecting in electric polarization reversal.
This work was supported by the APVV-SK-CZ-RD-21-0114, FLAG ERA JTC 2021 2DSOTECH, and IMPULZ IM-2021-42 research grants.
Keywords: first-principles study; helical states; electric polarization