A current paper printed in Nature describes a fingernail-sized gadget developed by a Harvard College crew. This gadget can twist skinny supplies at will, eliminating the necessity to create twisted units individually.
Six years in the past, a discovery that fully modified the sector of condensed-matter physics was made: ultra-thin carbon stacked in two barely asymmetrical layers grew to become a superconductor, and {the electrical} properties of the layers could possibly be switched by various the twist angle between them.
Yuan Cao, a current Harvard Junior Fellow and MIT graduate scholar, was the primary creator of the seminal 2018 paper describing “magic-angle graphene superlattices,” which launched the sector of “twistronics. ”
Constructing on this foundational work, Cao and colleagues—together with Harvard physicists Amir Yacoby, Eric Mazur, and others—have developed a technique to extra simply twist and examine quite a lot of supplies, opening up additional analysis in twistronics.
These extremely manipulable, skinny, two-dimensional supplies maintain vital potential for developments in quantum computing, photo voltaic cells, and higher-performance transistors.
This improvement makes twisting as simple as controlling the electron density of 2D supplies. Controlling density has been the first knob for locating new phases of matter in low-dimensional matter, and now, we will management each density and twist angle, opening countless prospects for discovery.
Amir Yacoby, Professor, Division of Physics and Utilized Physics, Harvard College
In Pablo Jarillo-Herrero’s lab at MIT, Yuan Cao first created twisted bilayer graphene as a graduate scholar. Whereas the achievement was groundbreaking, it was muted by the problem of replicating the exact twist.
On the time, every twisted gadget needed to be made by hand, making them distinctive and labor-intensive. Based on Cao, the crew wanted tens and even tons of of units to conduct their experiments, main them to ponder the thought of making “one device to twist them all”—a micromachine able to arbitrarily twisting two layers of fabric, eliminating the necessity for quite a few samples.
The researchers developed the MEGA2D, or micro-electromechanical system-based generic actuation platform for 2D supplies. This novel equipment, designed in collaboration between the labs of Amir Yacoby and Eric Mazur, will be utilized to graphene and different supplies.
By having this new ‘knob’ by way of our MEGA2D expertise, we envision that many underlying puzzles in twisted graphene and different supplies could possibly be resolved in a breeze. It can definitely additionally deliver different new discoveries alongside the best way.
Yuan Cao, Assistant Professor, College of California Berkeley
The scientists demonstrated the utility of their equipment through the use of two items of hexagonal boron nitride, a cloth intently associated to graphene. They had been in a position to look at the optical properties of the bilayer gadget and located proof of quasiparticles with fascinating topological traits.
The simplicity of the brand new system opens up quite a few scientific prospects. For instance, it may be used to create mild sources for low-loss optical communication by leveraging hexagonal boron nitride twistronics.
“We hope that our approach will be adopted by many other researchers in this prosperous field, and all can benefit from these new capabilities,” Cao mentioned.
Haoning Tang, a Postdoctoral Researcher in Mazur’s lab and a Harvard Quantum Initiative fellow, is the paper’s first creator. Tang, who focuses on Nanoscience and Optics, famous that the event of MEGA2D concerned a protracted strategy of trial and error.
We didn’t know a lot about the right way to management the interfaces of 2D supplies in real-time, and the present strategies simply weren’t chopping it. After spending numerous hours within the cleanroom and refining the MEMS design — regardless of many failed makes an attempt — we lastly discovered the working answer after a couple of yr of experiments.
Haoning Tang, Postdoctoral Researcher, Quantum Initiative Fellow, and Examine First Writer, Harvard College
Tang added that every one nanofabrication passed off at Harvard’s Middle for Nanoscale Programs, the place workers offered invaluable technical help.
“The nanofabrication of a device combining MEMS technology with a bilayer structure is a veritable tour de force. Being able to tune the nonlinear response of the resulting device opens the door to a whole new class of devices in optics and photonics,” mentioned Mazur, the Balkanski Professor of Physics and Utilized Physics.
Federal funding for the analysis got here from the Protection Superior Analysis Tasks Company, the Military Analysis Workplace, the US Air Drive Workplace of Scientific Analysis, and the Nationwide Science Basis.
Journal Reference:
Tang, H., et al. (2024) On-chip multi-degree-of-freedom management of two-dimensional supplies. Nature. doi.org/10.1038/s41586-024-07826-x