Direct visualization of magnetic domains and moiré magnetism in twisted 2D magnets.

Song, Tiancheng; Sun, Qi-Chao; Anderson, Eric; Wang, Chong; Qian, Jimin; Taniguchi, Takashi; Watanabe, Kenji; McGuire, Michael A et al. · Science · 2021

basic_science · Level V

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Abstract

Moiré superlattices of twisted nonmagnetic two-dimensional (2D) materials are highly controllable platforms for the engineering of exotic correlated and topological states. Here, we report emerging magnetic textures in small-angle twisted 2D magnet chromium triiodide (CrI<sub>3</sub>). Using single-spin quantum magnetometry, we directly visualized nanoscale magnetic domains and periodic patterns, a signature of moiré magnetism, and measured domain size and magnetization. In twisted bilayer CrI<sub>3</sub>, we observed the coexistence of antiferromagnetic (AFM) and ferromagnetic (FM) domains with disorder-like spatial patterns. In twisted double-trilayer CrI<sub>3</sub>, AFM and FM domains with periodic patterns appear, which is in good agreement with the calculated spatial magnetic structures that arise from the local stacking-dependent interlayer exchange interactions in CrI<sub>3</sub> moiré superlattices. Our results highlight magnetic moiré superlattices as a platform for exploring nanomagnetism.