A superconductor made from germanium, a material commonly used to build computer chips, could one day create better and more reliable quantum computers.

Superconductors are materials that conduct electricity with no resistance, which is useful if you are making any sort of electrical device. They also maintain quantum coherence, which is beneficial if you are trying to build a useful quantum computer.

But while previous superconductors have tended to be unusual materials that wouldn’t be easy to incorporate into computer chips, at the University of Queensland, Australia, and his colleagues have created one from germanium, which is already widely used by the computing industry.

The researchers created their superconductor by infusing a film of germanium with gallium, a process known as doping. Previous research along these lines found that the combination eventually became unstable. To avoid this, the team used X-rays to force more gallium into the material and thus create uniform and stable patterns.

Like other known superconductors, however, this new material doesn’t work at room temperature. It needs to be cooled to 3.5 kelvin (-270°C/-453°F).

at the University of Cambridge says that the superconductor’s need for extremely cold temperatures rules it out for use in consumer devices, but that it could be a perfect fit for quantum computing, which also tends to need super-cooling.

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“It could be transformational for quantum,” says Cardwell. “This gives a whole new level of functionality, because you’ve got a very cold environment anyway. That would be, I think, the obvious starting point.”

Jacobson says that previous work that layered superconductors on top of semiconductors, a key component of computing devices, caused defects in the crystal structure, which cause problems when it comes to applications. “Disorder is really a parasitic effect in quantum technology,” he says. “It causes absorption of your signals.”

But the new material allows layers of gallium-doped germanium and layers of silicon to sit on top of each other with a uniform crystal structure throughout, potentially allowing for the manufacture of chips that merge the best properties of semiconductors and superconductors.

A new way to make ultra-thin diamond wafers using sticky tape could help produce diamond-based electronics, which might one day be a useful alternative to silicon-based designs.

Diamond has unusual electronic properties: it is both a good insulator and allows electrons with certain energies to move with little resistance. This can translate to being able to handle higher energies with greater efficiency than conventional silicon chip designs.

However, producing working diamond chips requires large and very thin wafers, similar to the thin silicon wafers used to build modern computer chips, which have proved tricky to create.

Now, at the University of Hong Kong and his colleagues have found a way to produce extremely thin and flexible diamond wafers, using sticky tape.

Chu and his colleagues first implanted nano-sized diamonds in a small silicon wafer, then blew methane gas over it at high temperatures to form a continuous, thin diamond sheet. They then created a small crack on one side of the attached diamond sheet, before peeling off the diamond layer using regular sticky tape.

They found that this peeled diamond sheet was both extremely thin, at less than a micrometre, much thinner than a human hair, and smooth enough to allow for the kind of etching techniques used to produce silicon chips.

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“It is very reminiscent of the early days of graphene when Scotch tape was used to produce the first monolayer of graphene from graphite. I just never would have imagined the concept being applied to diamond,” says at the University of Warwick, UK.

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“This new edge-exposed exfoliation method will be an enabler for a multitude of device designs and experimental approaches,” says at the University of Cambridge. One area it could be particularly useful for is offering greater control in quantum devices that use diamonds as sensors, he says.

The diamond membranes Chu and his colleagues can produce are about 5 centimetres across, which shows that the method works as a proof of principle, says at the University of Cambridge, but it is still smaller than the larger 20-30 centimetres that is standard to many wafer processes, and it isn’t clear whether the new method can be scaled up, he says.

The wafers produced also appear to be polycrystalline, which are less smooth and regular than monocrystalline diamond, and this could limit its use for some applications, says Macpherson.