Fig. 1: Evolution of competing magnetic orders in tDB CrI3.
From: Super-moiré spin textures in twisted two-dimensional antiferromagnets
a, Schematic of the scanning quantum microscopy technique for the visualization of magnetic textures in tDB CrI3. An NV centre (red spin) is located at the apex of a diamond pillar. The NV is initialized by a green laser and controlled by a microwave (MW) signal. The sample device consists of two sheets of bilayer CrI3 with a twist angle θ between them. b, Schematic of moiré-modulated magnetic interactions at near-zero twist angle, showing the rhombohedral stacking region (R, shaded red) and monoclinic stacking region (M, shaded blue) are well separated. Thus, the magnetic texture closely follows the underlying moiré lattice, forming sharp magnetic domain walls. In this regime, a < aM, where a and aM denote the length scale of magnetic texture and moiré wavelength, respectively. c, Schematic of competing magnetic orders at larger twist angles, where FM- and AFM-favoured regions shift towards AA sites. Magnetic competition drives strong non-collinear spin textures, with magnetic domains extending beyond a single moiré unit cell. In this regime, a > aM. d–f, Atomistic simulated normalized magnetization maps over a 450-nm region for twist angles of 0.5° (d), 1.1° (e) and 2° (f). Only magnetic competition of J⊥ and J∥ is considered. A cross-section of the magnetization from a single layer of the tDB CrI3 shows the merging of moiré cells into larger magnetic textures with increasing twist angle. White dots in the background mark the positions of underlying monoclinic sites for each twist angle. g, Schematic illustration of topological magnetic textures in relation to the moiré stacking. The arrows indicate the spin configuration in the 2D magnet, while the grey lattice beneath represents the moiré superlattice. The shaded holes artistically depict regions of distinct stacking. A representative moiré unit cell is outlined by a blue hexagon. The emergent super-moiré magnetic textures span multiple moiré unit cells, with characteristic length scales exceeding 100 nm.
