A latest paper revealed in Nature describes a fingernail-sized system developed by a Harvard College group. This system 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 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 could possibly be switched by various the twist angle between them.
Yuan Cao, a latest Harvard Junior Fellow and MIT graduate scholar, was the primary writer 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 a wide range 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 growth 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 system needed to be made by hand, making them distinctive and labor-intensive. In line with Cao, the group wanted tens and even a whole bunch 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’ through our MEGA2D expertise, we envision that many underlying puzzles in twisted graphene and different supplies could possibly be resolved in a breeze. It can actually 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 by utilizing two items of hexagonal boron nitride, a fabric intently associated to graphene. They had been capable of look at the optical properties of the bilayer system 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 approach will be adopted by many other researchers in this prosperous field, and all can benefit from these new capabilities,” Cao stated.
Haoning Tang, a Postdoctoral Researcher in Mazur’s lab and a Harvard Quantum Initiative fellow, is the paper’s first writer. Tang, who makes a speciality of Nanoscience and Optics, famous that the event of MEGA2D concerned an extended strategy of trial and error.
We didn’t know a lot about methods 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 resolution after a couple of yr of experiments.
Haoning Tang, Postdoctoral Researcher, Quantum Initiative Fellow, and Examine First Creator, Harvard College
Tang added that each one nanofabrication passed off at Harvard’s Middle for Nanoscale Methods, the place employees supplied invaluable technical assist.
“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,” stated 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 Pressure 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