Graphene ‘cleanroom’ raises the game for quantum research

Professor Andre Geim’s team at the National Graphene Institute (NGI) fashioned a ‘proximity mirror’ using bulk graphite – consisting of layers of graphene – three atoms above a single sheet of graphene.

It had the effect of cancelling out disruption from electric fields, minimising interference and impurities, explained professor Danii Domaretskiy, first author of the research paper published in Nature.

He likened the process to creating “the ultimate clean room, but for electrons".

"We’ve removed almost all the ‘dirt’ that disrupts smooth flow of electric current. You can suddenly see effects that were hidden, like wiping clean a fogged-up window," stated Domaretskiy.

Reducing the disorder in graphene by a factor of 100 resulted in only one uncontrolled electron per 100 million carbon atoms remaining across an entire device.

Effects previously obscured could be observed at magnetic field strengths below the 50 Gauss minimum for a fridge magnet.

“Now that we know how to make things this clean, it opens the door to exploring phenomena that were out of reach,” said co-author Dr Zefei Wu.

The researchers said the technique, applied for probing quantum phenomena in two-dimensional materials, would allow the possibility of new discoveries in superconductivity, magnetism and exotic quantum phases.

The NGI, based at the University of Manchester, collaborated for the project with Lancaster University, the National University of Singapore, and the National Institute for Materials Science in Japan.

Pic: Shutterstock (Maksym Dehil) 

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