Researchers are creating new moiré supplies on the nanometer scale utilizing superior DNA nanotechnology: DNA moiré superlattices type when two periodic DNA lattices are overlaid with a slight rotational twist or positional offset. This creates a brand new, bigger interference sample with utterly completely different bodily properties. A brand new method developed by researchers on the College of Stuttgart and the Max Planck Institute for Strong State Analysis not solely facilitates the advanced development of those superlattices; it additionally unlocks solely new design prospects on the nanoscale. The research has been printed within the journal Nature Nanotechnology.
Moiré superlattices have turn into central to trendy condensed matter and photonic analysis. Nevertheless, realizing such buildings usually includes delicate and laborious fabrication steps, together with exact alignment and switch of pre-fabricated layers below extremely managed circumstances. “Our method bypasses conventional constraints of making moiré superlattices,” says Prof. Laura Na Liu, director of the twond Physics Institute on the College of Stuttgart.
New paradigm for the development of moiré tremendouslattices
“In contrast to standard strategies that depend on mechanical stacking and twisting of two-dimensional supplies, our platform leverages a bottom-up meeting course of,” explains Laura Na Liu. The meeting course of refers back to the linking of particular person DNA strands to type bigger, ordered buildings. It’s based mostly on self-organization: The DNA strands be a part of collectively with out exterior intervention, solely by molecular interactions. The Stuttgart analysis workforce is benefiting from this particular characteristic. “We encode the geometric parameters of the superlattice — akin to rotation angle, sublattice spacing, and lattice symmetry — immediately into the molecular design of the preliminary construction, often called the nucleation seed. We then enable all the structure to self-assemble with nanometer precision.” The seed acts as a structural blueprint, directing the hierarchical development of 2D DNA lattices into exactly twisted bilayers or trilayers, all achieved inside a single solution-phase meeting step.
Exploring Uncharted Territory: Moiré Constructions on the Intermediate Nanometer Scale
Whereas moiré superlattices have been extensively explored on the atomic (angstrom) and photonic (submicron) scales, the intermediate nanometer regime, the place each molecular programmability and materials performance converge, has remained largely inaccessible. The Stuttgart researchers have closed this hole with their present research. The workforce combines two highly effective DNA nanotechniques: DNA origami and single-stranded tile (SST) meeting.
Utilizing this hybrid technique, the researchers constructed micrometer-scale superlattices with unit cell dimensions as small as 2.2 nanometers, that includes tunable twist angles and varied lattice symmetries, together with sq., kagome, and honeycomb. In addition they demonstrated gradient moiré superlattices, by which the twist angle and therefore moiré periodicity varies repeatedly throughout the construction. “These superlattices reveal well-defined moiré patterns below transmission electron microscopy, with noticed twist angles carefully matching these encoded within the DNA origami seed,” notes co-author Prof. Peter A. van Aken from the Max Planck Institute for Strong State Analysis.
The research additionally introduces a brand new development course of for moiré superlattices. The method is initiated by spatially outlined seize strands on the DNA seed that act as molecular ‘hooks’ to exactly bind SSTs and direct their interlayer alignment. This allows the managed formation of twisted bilayers or trilayers with precisely aligned SST sublattices.
Broad implications throughout molecular engineering, nanophotonics, spintronics, and supplies science
Their excessive spatial decision, exact addressability, and programmable symmetry endow the brand new moiré superlattices with vital potential for various functions in analysis and expertise. For instance, they’re ideally suited scaffolds for nanoscale parts — akin to fluorescent molecules, metallic nanoparticles or semiconductors in personalized 2D and 3D architectures.
When chemically remodeled into inflexible frameworks, these lattices may very well be repurposed as phononic crystals or mechanical metamaterials with tunable vibrational responses. Their spatial gradient design additionally opens avenues for transformation optics and gradient-index photonic units, the place moiré periodicity may steer gentle or sound alongside managed trajectories.
One significantly promising utility lies in spin-selective electron transport. DNA has been proven to behave as a spin filter, and these well-ordered superlattices with outlined moiré symmetries may function a platform to discover topological spin transport phenomena in a extremely programmable setting.
“This isn’t about mimicking quantum supplies,” says Laura Na Liu. “It is about increasing the design area and making it potential to construct new varieties of structured matter from the underside up, with geometric management embedded immediately into the molecules.”
