A latest paper revealed in Nature describes a fingernail-sized machine developed by a Harvard College staff. This machine can twist skinny supplies at will, eliminating the necessity to create twisted gadgets individually.
Six years in the past, a discovery that utterly modified the sphere 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 may very well be switched by various the twist angle between them.
Yuan Cao, a latest Harvard Junior Fellow and MIT graduate scholar, was the primary creator of the seminal 2018 paper describing “magic-angle graphene superlattices,” which launched the sphere of “twistronics. ”
Constructing on this foundational work, Cao and colleagues—together with Harvard physicists Amir Yacoby, Eric Mazur, and others—have developed a way to extra simply twist and research quite a lot of supplies, opening up additional analysis in twistronics.
These extremely manipulable, skinny, two-dimensional supplies maintain important 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 are able to management each density and twist angle, opening limitless potentialities 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 machine needed to be made by hand, making them distinctive and labor-intensive. In response to Cao, the staff wanted tens and even a whole lot of gadgets to conduct their experiments, main them to ponder the thought of making “one machine to twist all of them”—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, might be utilized to graphene and different supplies.
By having this new ‘knob’ through our MEGA2D know-how, we envision that many underlying puzzles in twisted graphene and different supplies may very well be resolved in a breeze. It should 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 have been capable of look at the optical properties of the bilayer machine and located proof of quasiparticles with fascinating topological traits.
The simplicity of the brand new system opens up quite a few scientific potentialities. For instance, it may be used to create gentle sources for low-loss optical communication by leveraging hexagonal boron nitride twistronics.
“We hope that our method will likely be adopted by many different researchers on this affluent discipline, and all can profit 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 makes a speciality of Nanoscience and Optics, famous that the event of MEGA2D concerned a protracted technique of trial and error.
We didn’t know a lot about how you can management the interfaces of 2D supplies in real-time, and the prevailing strategies simply weren’t slicing 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 resolution after a few 12 months of experiments.
Haoning Tang, Postdoctoral Researcher, Quantum Initiative Fellow, and Research First Creator, Harvard College
Tang added that each one nanofabrication befell at Harvard’s Heart for Nanoscale Techniques, the place workers supplied invaluable technical help.
“The nanofabrication of a tool combining MEMS know-how with a bilayer construction is a veritable tour de pressure. Having the ability to tune the nonlinear response of the ensuing machine opens the door to a complete new class of gadgets 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 Initiatives Company, the Military Analysis Workplace, the US Air Power 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
