In the fast moving field of two dimensional materials, even a slight rotational shift between layers can dramatically change how a material behaves. Scientists previously discovered that when atom thin crystals are stacked with a small angular mismatch, their electronic properties can transform. This approach, known as moiré engineering, has become a key strategy for designing new forms of quantum matter.
Now researchers report in Nature Nanotechnology that magnetism can also behave in surprising ways under these conditions. In twisted antiferromagnetic layers, magnetic spin patterns are not limited to the small repeating moiré unit cell. Instead, they can spread into much larger, topological structures that extend across hundreds of nanometers.
Giant Magnetic Textures Beyond the Moiré Pattern
In most moiré systems, the size of physical effects is determined directly by the interference pattern created when two crystal lattices overlap. Magnetic order in stacked van der Waals magnets was widely expected to follow this same length scale. The new findings challenge that assumption.
The team examined twisted double bilayer chromium triiodide (CrI3) using scanning nitrogen-vacancy magnetometry, a technique that images magnetic fields with nanoscale precision. They observed magnetic textures reaching distances of up to ~300 nm, far exceeding the size of a single moiré cell and roughly ten times larger than the underlying wavelength.
A Counterintuitive Twist Angle Effect
The results reveal an unexpected pattern. When the twist angle becomes smaller, the moiré wavelength increases. However, the magnetic textures do not simply grow along with it. Instead, their size changes in the opposite way, reaching a maximum near 1.1° and disappearing above ~2°.
This reversal shows that magnetism is not just copying the moiré template. Rather, it arises from a balance between several competing forces, including exchange interactions, magnetic anisotropy and Dzyaloshinskii-Moriya interactions. All of these are subtly adjusted by how the layers are rotated relative to one another. Large scale spin dynamics simulations back up this interpretation, demonstrating the formation of extended Néel-type antiferromagnetic skyrmions that span multiple moiré cells.
Skyrmions and Low Power Spintronics
These findings matter beyond basic physics. Skyrmions are promising for future information technologies because they are small, stable and protected by their topology. They can also be moved using very little energy. Creating them simply by adjusting the twist angle, without lithography, heavy metals or strong electric currents, provides a clean and geometry driven path toward low power spintronic devices.
The researchers describe this phenomenon as super-moiré spin order, highlighting that twist engineering operates across multiple scales. A change in atomic alignment can generate topological structures on much larger, mesoscale distances. This challenges the long held idea that moiré physics is only a local effect and positions twist angle as a powerful thermodynamic control parameter capable of tuning exchange, anisotropy and chiral interactions to stabilize topological phases.
From a practical standpoint, these large and robust Néel-type skyrmionic textures are well suited for integration into devices. Their larger size makes them easier to detect and manipulate. At the same time, their topological protection and insulating host material suggest extremely low energy loss during operation. As scientists continue to explore how geometry shapes quantum behavior, such emergent magnetic states could play an important role in developing energy efficient, post-CMOS computing technologies.
Dr. Elton Santos, Reader in Theoretical/Computational Condensed Matter Physics, University of Edinburgh, whose team led the modelling aspect of the project, said: “This discovery shows that twisting is not just an electronic knob, but a magnetic one. We’re seeing collective spin order self-organize on scales far larger than the moiré lattice. It opens the door to designing topological magnetic states simply by controlling angle, which is a remarkably simple handle with profound practical consequences.”
