01/28/2017 / By Daniel Barker
Since graphene’s discovery just over a decade ago, scientists have been exploring its remarkable properties and potential uses in a wide range of applications, including that of a superconductor.
Superconductivity is the ability of certain materials to enable the flow of an electric current with little or zero resistance. This is usually only achieved at very low temperatures, which makes superconductivity rather expensive and currently impractical for many applications. (RELATED: See more news about advances in science at Scientific.news.)
Early on, it was theorized that graphene might have superconductive properties, but until now, researchers have been unable to harness its potential without involving other materials in the process.
But now, a team of researchers have reported finding a method to unlock graphene’s superconductivity without having to insert calcium atoms into its latticework or place it on another superconducting material – the only methods discovered so far that were able to make graphene display superconductivity.
Graphene is an amazing material to begin with – it’s a two-dimensional sheet of carbon atoms that happens to be extremely strong, flexible, lightweight, and conductive. It has the potential to revolutionize a number of technologies and its as-of-yet untapped properties include superconductivity – a theorized potential that now appears to have been confirmed.
As mentioned above, researchers have previously only been able to achieve superconductivity with graphene by using other materials in tandem with it. The latest research, conducted by a team of scientists at the University of Cambridge, involved a new approach – one that not only showed graphene is capable of achieving superconductivity on its own, but which also hinted at confirming another postulated theory regarding graphene’s mysterious superconductive properties.
From Science Daily:
“Until now, superconductivity in graphene has only been achieved by doping it with, or by placing it on, a superconducting material – a process which can compromise some of its other properties… But in the new study, researchers…managed to activate the dormant potential for graphene to superconduct in its own right. This was achieved by coupling it with a material called praseodymium cerium copper oxide (PCCO).”
Although the method appears to resemble those in which graphene was used in tandem with other materials, there was a difference in the results when PCCO was involved in the process:
“[T]he difference here is that PCCO is a type of superconducting material called a cuprate, which has well-understood electronic properties.
“So the team was able to clearly distinguish the superconductivity in PCCO from the superconductivity in graphene. And what they saw was crazier than they’d expected.”
The “crazy” thing the team observed was evidence of a rare and previously unverified type of superconductivity called a “p-wave” state.
Superconductivity involves the pairing of electrons in tandem to move through a material with zero resistance. This movement is characterized by specific types of spin alignment among the paired electrons.
In PCCO, for example, the spin alignment of the electron pairs is called a “d-wave” state. In contrast, the graphene electron pairs in the experiment appeared to act in the form of a p-wave state which, if true, proves the theory that the elusive p-wave state does exist.
And that means huge potential for graphene in the future.
“If p-wave superconductivity is indeed being created in graphene, graphene could be used as a scaffold for the creation and exploration of a whole new spectrum of superconducting devices for fundamental and applied research areas,” said Jason Robinson, one of the researchers.
Graphene could prove to be the means to achieving superconductivity above -269 degrees Celsius (-452.2 degrees Fahrenheit) – a significant step towards creating groundbreaking new technologies that can be applied to medicine, electronics, power grids, energy storage, and many other areas.