Observation of stacking engineered magnetic phase transitions within moiré supercells of twisted van der Waals magnets

Senlei Li; Zeliang Sun; Nathan J McLaughlin; Afsana Sharmin; Nishkarsh Agarwal; Mengqi Huang; Suk Hyun Sung; Hanyi Lu; Shaohua Yan; Hechang Lei; Robert Hovden; Hailong Wang; Hua Chen; Liuyan Zhao; Chunhui Rita Du

doi:10.1038/s41467-024-49942-2

Observation of stacking engineered magnetic phase transitions within moiré supercells of twisted van der Waals magnets

Nat Commun. 2024 Jul 8;15(1):5712. doi: 10.1038/s41467-024-49942-2.

Authors

Senlei Li^#¹, Zeliang Sun^#², Nathan J McLaughlin³, Afsana Sharmin⁴, Nishkarsh Agarwal⁵, Mengqi Huang¹, Suk Hyun Sung⁵, Hanyi Lu³, Shaohua Yan^{6

7}, Hechang Lei^{6

7}, Robert Hovden⁵, Hailong Wang¹, Hua Chen^{4

8}, Liuyan Zhao⁹, Chunhui Rita Du^{10

11}

Affiliations

¹ School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
² Department of Physics, the University of Michigan, Ann Arbor, MI, 48109, USA.
³ Department of Physics, University of California, San Diego, La Jolla, San Diego, CA, 92093, USA.
⁴ Department of Physics, Colorado State University, Fort Collins, CO, 80523, USA.
⁵ Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.
⁶ Department of Physics, Beijing Key Laboratory of Optoelectronic Functional Materials MicroNano Devices, Renmin University of China, Beijing, 100872, China.
⁷ Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, 100872, China.
⁸ School of Advanced Materials Discovery, Colorado State University, Fort Collins, CO, 80523, USA.
⁹ Department of Physics, the University of Michigan, Ann Arbor, MI, 48109, USA. lyzhao@umich.edu.
¹⁰ School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA. cdu71@gatech.edu.
¹¹ Department of Physics, University of California, San Diego, La Jolla, San Diego, CA, 92093, USA. cdu71@gatech.edu.

^# Contributed equally.

Abstract

Recent demonstrations of moiré magnetism, featuring exotic phases with noncollinear spin order in the twisted van der Waals (vdW) magnet chromium triiodide CrI₃, have highlighted the potential of twist engineering of magnetic (vdW) materials. However, the local magnetic interactions, spin dynamics, and magnetic phase transitions within and across individual moiré supercells remain elusive. Taking advantage of a scanning single-spin magnetometry platform, here we report observation of two distinct magnetic phase transitions with separate critical temperatures within a moiré supercell of small-angle twisted double trilayer CrI₃. By measuring temperature-dependent spin fluctuations at the coexisting ferromagnetic and antiferromagnetic regions in twisted CrI₃, we explicitly show that the Curie temperature of the ferromagnetic state is higher than the Néel temperature of the antiferromagnetic one by ~10 K. Our mean-field calculations attribute such a spatial and thermodynamic phase separation to the stacking order modulated interlayer exchange coupling at the twisted interface of moiré superlattices.

Abstract

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