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Computers that can make use of the “spooky” properties of quantum mechanics may sound alluring, but first they must overcome a massive manufacturing disadvantage.

Nanoscale layer of a superconducting material on top of a nitride-semiconductor substrate

Scientists from Japan may have found the answer to quantum’s computing biggest disadvantage through their demonstration of how a superconducting material, niobium nitride, can be added to a nitride-semiconductor substrate as a flat, crystalline layer. This process may lead to the easy manufacturing of quantum qubits connected with conventional computer devices.

The problem with quantum computing adaptation

The processes used to manufacture conventional silicon microprocessors have matured over decades and are constantly being refined and improved. In contrast, most quantum computing architectures must be designed mostly from scratch. However, finding a way to add quantum capabilities to existing fabrication lines, or even integrate quantum and conventional logic units in a single chip, might be able to vastly accelerate the adoption of these new systems.

Meet Niobium Nitride

Now, a team of researchers at the Institute of Industrial Science at The University of Tokyo have shown how thin films of niobium nitride (NbNx) can be grown directly on top of an aluminum nitride (AlN) layer. Niobium nitride can become superconducting at temperatures colder than about 16 degrees above absolute zero. As a result, it can be used to make a superconducting qubit when arranged in a structure called a Josephson junction.

Why NbNx works so well

The scientists investigated the impact of temperature on the crystal structures and electrical properties of NbNx thin films grown on AlN template substrates. They showed that the spacing of atoms in the two materials was compatible enough to produce flat layers.

“We found that because of the small lattice mismatch between aluminum nitride and niobium nitride, a highly crystalline layer could grow at the interface.”

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Nanoscale layer of a superconducting material on top of a nitride-semiconductor substrate via Eureka Alert by Institute of Industrial Science, The University of Tokyo with usage type - News Release Media

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Nanoscale layer of a superconducting material on top of a nitride-semiconductor substrate via Eureka Alert by Institute of Industrial Science, The University of Tokyo with usage type - News Release Media