Exploring moiré skyrmions in twisted double bilayer and double trilayerCrI3.

Moiré magnets have emerged as intriguing platforms for hosting exotic magnetic states due to the competing interactions within these materials. Recent experiments have reported noncollinear magnetic states in moiréCrI3, particularly focusing on twisted double bilayer (tDB) and double trilayer (tDT) configurations. However, atomistic simulations of moiréCrI3have largely been limited to the bilayer case. Here, we use stochastic Landau-Lifshitz-Gilbert simulations to investigate skyrmion nucleation in tDB and tDTCrI3and to estimate the threshold Dzyaloshinskii-Moriya interaction (th-DMI) required for their stabilization. Our findings show that the th-DMI decreases significantly with reduced twist angles. Above this threshold, three skyrmions nucleate at the monoclinic regions of the moiré supercell, randomly distributing across the interfacial layers and imprinting onto adjacent layers. Additionally, a substrate-induced DMI further reduces the th-DMI without affecting skyrmion localization. These results suggest that small twist angles and substrate-induced DMI can facilitate skyrmion formation in moiré structures.