Evidence of Moiré-induced Noncollinear Spin Textures in Twisted Layered Antiferromagnet Homostructures

Moiré engineering developed recently provides an unprecedented venue to design magnetic properties at the atomic scale in the two dimensions. Specifically, in moiré magnets made by twisting two-dimensional (2D) magnetic atomic crystals, the periodic modulations of interlayer exchange coupling, in both strength and sign, can alter the magnetic ground states of constituent 2D magnets and introduce new 2D magnetic phases. While the large pool of 2D magnets discovered so far only features collinear spin structures including simple ferromagnetism and antiferromagnetism, moiré magnets can introduce emergent noncollinear spin textures such as skyrmion lattices and chiral magnetism. In this talk, I will present the observation of noncollinear magnetic order in twisted double bilayer CrI₃ through careful magnetic circular dichroism measurements, as well as the evolution of the order as functions of temperature, magnetic field and twist angle.