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arXiv · 2204.01636

Evidence of Noncollinear Spin Texture in Magnetic Moir\'e Superlattices

Hongchao Xie·Xiangpeng Luo·Zhipeng Ye·Gaihua Ye·Haiwen Ge·Shaohua Yan·Yang Fu·Shangjie Tian·Hechang Lei·Kai Sun·Rui He·Liuyan Zhao
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Abstract

Moir\'e magnetism, parallel with moir\'e electronics that has led to novel correlated and topological electronic states, emerges as a new venue to design and control exotic magnetic phases in twisted magnetic two-dimensional(2D) crystals. Here, we report direct evidence of noncollinear spin texture in 2D twisted double bilayer (tDB) magnet chromium triiodide (CrI$_3$). Using magneto-optical spectroscopy in tDB CrI$_3$, we revealed the presence of a net magnetization, unexpected from the composing antiferromagnetic bilayers with compensated magnetizations, and the emergence of noncollinear spins, originated from the moir\'e exchange coupling-induced spin frustrations. Exploring the twist angle dependence, we demonstrated that both features are present in tDB CrI$_3$ with twist angles from 0.5$^o$ to 5$^o$, but are most prominent in the 1.1$^o$ tDB CrI$_3$. Focusing on the temperature dependence of the 1.1$^o$ tDB CrI$_3$, we resolved the dramatic suppression in the net magnetization onset temperature and the significant softening of noncollinear spins, as a result of the moir\'e induced frustration. Our results demonstrate the power of moir\'e superlattices in introducing novel magnetic phenomena that are absent in natural 2D magnets.

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Hongchao Xie, Xiangpeng Luo, Zhipeng Ye, Gaihua Ye, Haiwen Ge, Shaohua Yan, Yang Fu, Shangjie Tian, Hechang Lei, Kai Sun, Rui He, Liuyan Zhao. 2022-04-04. Evidence of Noncollinear Spin Texture in Magnetic Moir\'e Superlattices. https://doi.org/10.1038/s41567-023-02061-z

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