Twisting light with a micromachine. (Image courtesy of Yuan Cao)In a twist
Just a few years ago, researchers discovered that changing the angle between two layers of graphene, an atom-thick sheet of carbon, also changed the material’s electronic and optical properties. They then learned that a “twist” of 1.1 degrees — dubbed the “magic” angle — could transform this metallic material into an insulator or a superconductor, a finding that ignited excitement about a possible pathway to new quantum technologies.
To study the physics underlying this phenomenon, “twistronics” researchers had to produce tens to hundreds of different configurations of the twisted graphene structures — a costly and labor-intensive process. But a team of researchers led by Yuan Cao, the leading discoverer of the magic angle in 2018 and now an assistant professor of electrical engineering and computer sciences, has created a device that can twist a single structure in countless ways.
In a study, the researchers demonstrated the world’s first micromachine that can twist 2D materials at will. The fingernail-sized, on-chip platform, called MEGA2D, uses microelectro-mechanical systems (MEMS) to conduct voltage-controlled manipulation of 2D materials — which are only nanometers thick — with unprecedented flexibility and precision.
“Our work extends the capabilities of existing technologies in manipulating low-dimensional quantum materials,” said Cao. “It also paves the way for novel hybrid 2D and 3D structures, with promising implications in condensed-matter physics, quantum optics and related fields.”
According to the researchers, the MEGA2D platform has several potential applications beyond twistronics, including use as a tunable light source for classic, or standard, light bulbs as well as for quantum versions. For now, the team believes that the true power of the MEGA2D technology lies in fundamental research. “It will certainly also bring other new discoveries along the way,” said Cao.
Learn more: World’s first micromachine twists 2D materials at will; On-chip multi-degree-of-freedom control of two-dimensional materials (Nature)