High temperature superconductivity breakthrough claimed

Researchers from the University of Cambridge say they have made a breakthrough in identifying what enables high temperature superconductivity.

According to the team, ripples of electrons – known as charge density waves – create twisted 'pockets' of electrons and it is these which enable superconductivity.



Low temperature superconductors, which need to be cooled close to absolute zero, were first identified in the early 20th Century, but the search for high temperature superconductors has been more of a challenge, with the Cambridge team saying progress could be 'best described as random'.



"We don't know how to find new high temperature superconductors because we don't actually know what ingredients are responsible for creating high temperature superconductivity in the first place," said Dr Suchitra Sebastian of the Cavendish Laboratory. "We know there's some sort of glue which causes the electrons to pair up, but we don't know what that glue is."



In order to discover what enables high temperature superconductivity, the researchers worked backwards: by determining what properties the materials have in their normal, non superconducting state, they hoped to understand what was causing superconductivity.



Working with magnetic fields as strong as 100Tesla, the researchers were able to kill the superconducting effect in cuprates. The experiments showed what the researchers said was 'a peculiar undulating twisted pocket geometry, similar to Jenga bricks, where each layer goes in a different direction to the one above or beneath it'.



These results showed superconductivity is weakest in these pocket locations and the origin to be charge density waves. It is this normal state, the team added, that is overridden to yield superconductivity in cuprate superconductors.



"By identifying other materials which have similar properties, hopefully it will help us find new superconductors at higher and higher temperatures, even perhaps materials which are superconductors at room temperature, which would open up a huge range of applications," Dr Sebastian concluded.

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