Exploring moiré skyrmions in twisted double bilayer and double trilayer CrI3

Moir & eacute; 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 moir & eacute; CrI3, particularly focusing on twisted double bilayer (tDB) and double trilayer (tDT) configurations. However, atomistic simulations of moir & eacute; CrI3 have largely been limited to the bilayer case. Here, we use stochastic Landau-Lifshitz-Gilbert simulations to investigate skyrmion nucleation in tDB and tDT CrI3 and 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 moir & eacute; 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 moir & eacute; structures.