Emergent Moiré Magnetism in Near 0^○ and Near 180^○ Twisted Double Bilayer CrI₃

Moiré superlattices have been proven to be a fruitful venue in design physical properties of 2D materials. Here, we focus on moiré magnetism arising from twisting two 2D magnetic layers. We choose bilayer CrI3 as the composing layer to construct twisted double bilayer CrI3 moiré superlattices and explore the introduction of new magnetic properties that are not present in natural bilayer and four-layer CrI3. We note that due to the crystal field imposed by the Iodium octahedral cage, CrI3 monolayer possess an out-of-plane 3-fold rotational symmetry, but not a 2-fold one, resulting in differences in structure, and hence magnetism, between the near 0o and near 180o twisted CrI3. In this talk, we will present the experimental results for both cases, to illustrate their distinct magnetic ground states and collective excitations.