DTU Physics researchers have created the tiniest record ever sliced, measuring just 40 micrometres in diameter. The single, which features the opening 25 seconds of the Christmas classic “Rocking Around the Christmas Tree,” was cut using a new nano-sculpting machine, the Nanofrazor, which Heidelberg Instruments just bought. The Nanofrazor can carve 3D patterns into surfaces with nanoscale precision, enabling researchers to construct new nanostructures that might pave the way for new technologies such as quantum devices, magnetic sensors, and electron optics.
“I’ve been doing lithography for 30 years, and even though we’ve had this equipment for a while, it still seems science fiction. We’ve conducted several tests, such as replicating the Mona Lisa in a 12 by 16-micrometer area with a pixel size of 10 nanometers. We’ve also printed an 8 by 12-micrometer photograph of DTU’s founder, Hans Christian rsted, with a pixel resolution of 2,540,000 DPI. “We could write our signatures on a red blood cell with this instrument to get a notion of the size we’re operating at,” explains DTU Physics Professor Peter Bggild.
“The most radical aspect is that we can generate free-form 3D landscapes at such a high resolution—this gray-scale nanolithography is a major game changer for our study.”
In stereo, a nanoscale Christmas record
The Nanofrazor is not a printer that adds material to a medium; rather, it is a CNC (computer numerical control) machine that removes material at specific spots, leaving the desired form behind. The final image in the instance of the small portraits of Mona Lisa and H.C. rsted is determined by the elimination of polymer line by line until a flawless gray-scale image emerges. The concept of cutting a nanoscale record came naturally to Peter Bggild, an amateur musician and vinyl record collector.
“We figured we’d attempt printing a record. We took a clip of ‘Rocking Around The Christmas Tree’ and cut it exactly like a regular record—but since we’re working on the nanoscale, this one won’t play on your typical turntable. The Nanofrazor was used as a record-cutting lathe, transforming an audio input into a helical groove on the medium’s surface. The medium in this situation is a different polymer than vinyl.
“We even encoded the music in stereo—the lateral wriggles are the left channel, while the depth modulation is the right channel. It might be too impractical and costly to become a hit record. To read the groove, you’ll need an atomic force microscope or the Nanofrazor, but it’s certainly achievable.”
High-performance, low-cost nanostructures
The NOVO Foundation grant BIOMAG, which enabled the Nanofrazor idea, is not about making Christmas records or printing portraits of celebrities. Other proposals are in the works for Peter Bggild and his colleagues Tim Booth and Nolan Lassaline. They anticipate that the Nanofrazor will enable them to sculpt 3D nanostructures in highly accurate detail at high speed and cheap cost, which is now unattainable with conventional tools.
“We deal with 2D materials, and when these ultrathin materials are properly placed down over 3D landscapes, they follow the curves of the surface. In a nutshell, they curve, which is a powerful and altogether new technique of ‘programming’ materials to do things that no one would have believed conceivable even fifteen years ago. For example, when bent precisely, graphene acts as if there is a massive magnetic field when, in reality, there is none. “And we can bend it exactly right using the Nanofrazor,” Peter Bggild explains.
“The fact that we can now correctly sculpt the surfaces with nanoscale accuracy at very much the speed of imagination is a game changer for us,” says associate professor Tim Booth. We have a lot of ideas for what we should do next, and we feel that this machine will greatly speed up the prototyping of new structures. Within the BIOMAG project, our primary objective is to create innovative magnetic sensors for detecting currents in the live brain. Nonetheless, we look forward to finely constructed potential landscapes that will allow us to better govern electron waves. There is a lot of work to be done.”
Nolan Lassaline, a postdoc who worked on the Christmas record, wants to make “quantum soap bubbles” out of graphene. He plans to utilise the Nanofrazor to investigate new methods of organising nanomaterials and to create revolutionary methods of controlling electrons in atomically thin materials.
“Quantum soap bubbles are smooth electrical potentials with intentionally designed defects. This allows us to control how electrons flow in graphene. “We intend to understand how electrons travel in manufactured disordered potentials and see whether this can be used as a new platform for improved neural networks and quantum information processing,” Lassaline explains.
The Nanofrazor system is currently a component of the DTU Physics NANOMADE production facility for air-sensitive 2D materials and devices, as well as E-MAT, a larger ecosystem for air-sensitive nanomaterials processing and fabrication coordinated by Prof. Nini Pryds, DTU Energy.
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