Moiré magnetism featured by stacking engineered atomic registry and lattice interactions has recently emerged as an appealing quantum state of matter at the forefront of condensed matter physics research. Nanoscale imaging of moiré magnets is highly desirable and serves as a prerequisite to investigate a broad range of intriguing physics underlying the interplay between topology, electronic correlations, and unconventional magnetism. In this talk, I will present our recent work on using nitrogen-vacancy (NV) centers to perform nanoscale quantum sensing and imaging of magnetic domains and spin fluctuations in twisted double trilayer (tDT) chromium triiodide CrI3. We show that intrinsic moiré domains of opposite magnetizations appear over arrays of moiré supercells in low-twist-angle tDT CrI3 [1]. In addition, spin fluctuations measured in tDT CrI3 reveal two distinct magnetic phase transitions with separate critical temperatures within a moiré supercell [2]. Our results enrich the current understanding of exotic magnetic phases sustained by moiré magnetism and highlight the opportunities provided by quantum spin sensors in probing microscopic spin related phenomena on two-dimensional flatland. Lastly, I will extend my discussion to briefly present our ongoing efforts on exploring next-generation van der Waals quantum sensing technologies using color centers beyond NVs [3, 4, 5].
*This work was primarily supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), under award No. DE-SC0024870 (quantum sensing measurements). Development of the cryogenic scanning NV microscopy was supported by the Air Force Office of Scientific Research (AFOSR) under grant No. FA9550-25-1-0082. Instrumental development for device characterizations was partially supported by the Office of Naval Research (ONR) under grant No. N00014-23-1-2146.
–
Publication:1. M. Huang et al., Nat. Commun. 14, 5259 (2023). 2. S. Li et al., Nat. Commun. 15, 5712 (2024). 3. M. Huang et al., Nat. Commun. 13, 5369 (2022). 4. J. Zhou et al., Sci. Adv. 10, eadk8495 (2024). 5. X. Zhang et al., arXiv:2502.04561 (2025).
