A small twist—and a material's properties change dramatically. When two atomically thin crystals are stacked on top of each other and slightly rotated, a large-scale moiré pattern emerges that reshapes the movement and interaction of electrons. This is exactly how twistronics works—a field that has already delivered superconductivity and fractional Chern insulators in graphene and transition metal dichalcogenides.
Researchers from more than a dozen institutions, including the Max Planck Institute for Chemical Physics of Solids in Dresden, analyzed nearly 9000 two-dimensional materials from computational databases. They applied extended topological quantum chemistry to describe the electronic properties and symmetries of the crystals. As a result, they identified 4073 materials with nontrivial topology or special constraints on the placement of electronic charge.
From this array, they selected particularly promising candidates for twisting: 61 semimetal and 1568 insulators. Their electronic bands make it possible to obtain narrow bands where electron interactions begin to dominate over their motion. Such conditions are favorable for superconductivity, magnetism, and fractional quantum states.
The candidates span a variety of crystal lattices—from hexagonal to oblique. This opens up the possibility of creating quantum simulators tailored to specific models: twisted square lattices can mimic the Hubbard model, which is important for high-temperature superconductivity, while rectangular ones can emulate the behavior of electrons in one-dimensional chains.
The theoretical findings have already been backed by experiment. The scientists grew bulk crystals of several candidates, including tin diselenide and hafnium disulfide, successfully exfoliated them down to monolayers, and assembled the first devices. In Dresden, under the leadership of Claudia Felser, they obtained materials of the required quality for further twisting and measurements at millikelvin temperatures.
Two new catalogs provide a systematic tool: one describes the electronic "building blocks," the second indicates which of them are best suited for twistronics. Researchers will now be able to select a material and twist angle for a specific question about quantum matter, rather than being limited to a few known platforms.
Experiment sometimes suggests questions that had never even occurred to anyone before.
