Researchers at the University of Bath have developed a technique to create monocrystalline flake devices so fine and pure they could outperform existing components for quantum computers.
The researchers made the discovery by exploring the junction between two layers of a superconductor – niobium diselenide – after the layers were separated, twisted 30 ° relative to each other, and then stamped together. This process created a superconducting quantum interferometer (aka “SQUID”) device: an extremely sensitive sensor used to measure magnetic fields.
SQUIDs, based on superconducting loops, are crucial components of MEG imaging and are also used in MRI; cardiography; mineral exploration; scanning microscopes; gravitational wave detection and in commercial quantum computers.
Although this work is still in its early stages, these new superconducting chips have the potential to play an important role in the development of quantum computing in the years to come.
“Due to their atomically perfect surfaces, which are almost entirely free from flaws, we see the potential for our crystalline flakes to play an important role in building quantum computers of the future,” said Properties expert Professor Simon Bending. magnetic superconductors. materials at the University of Bath and author of the Nano letters report.
“In addition, SQUIDs are ideal for studies in biology – for example, they are now used to trace the path of magnetically labeled drugs through the gut – so we are very excited to see how our devices might be developed in this. domain as well. .
“This is a completely new and unexplored approach to fabricating SQUIDs and a lot of research will still need to be done before these applications become a reality. “
The flakes from which these superconductors are made are extremely thin single crystals that bend easily, making them suitable for being incorporated into flexible electronics.
Because the bonds between the layers of the superconductor are so weak, the cleaved flakes – with their completely flat, flawless surfaces – create atomically sharp interfaces when they are re-stamped. This makes them ideal candidates for components of quantum computers.
Physicists were also able to show that the properties of their devices could be systematically adjusted by varying the angle of torsion between the two flakes.
While this isn’t the first time that layers of niobium diselenide have been stamped together to create a weak superconducting bond, it is the first demonstration of quantum interference between two such junctions modeled in a twisted pair of sequins. This effect allows physicists to modulate the maximum current that can flow through SQUIDs by applying a small magnetic field, thus creating a very sensitive field sensor.
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