Twisted materials unlock new quantum states, hinting at superconductors

A twist of just 1.1 degrees unlocked a surprising property in bilayer graphene, and the field gained major attention after this discovery. Researchers are extending this exploration beyond graphene to materials like halide perovskites and MXenes, observing altered exciton transport and unexpected superconductivity. New experimental tools, including quantum twisting microscopes that can vary twist angles in situ, are helping scientists explore previously inaccessible quantum states without strong magnetic fields, a development materials chemist Yury Gogotsi from Drexel University describes as capturing the imagination after the discovery that “you could take two layers of non-superconducting material, twist it by roughly one degree and it becomes superconductor.” The ability to finely control the stacking and rotation of two-dimensional materials is revealing unexpected quantum phenomena, with recent work demonstrating fractional quantum anomalous Hall states without the need for strong magnetic fields. This advancement stems from the manipulation of moiré superlattices, periodic patterns formed when two layers of material are slightly misaligned, and allows scientists to explore exotic electronic behaviors previously inaccessible. These states, where electrons appear to fractionate their charge, were observed in topological moiré materials featuring flat bands, marking the first instance of this behavior outside of high-magnetic-field experiments. Beyond graphene, the…