"Superconductivity in twisted bilayer graphene will teach us about superconductivity at much higher temperatures, temperatures that will be useful for real-world applications."Emilio Codecido, Ohio State University
Researchers at Ohio State University, in collaboration with scientists around the world, have made a discovery that could provide new insights into how superconductors might deliver energy more efficiently to power homes, industries and vehicles. Their work, reported in a paper in Science Advances, showed that graphene – a material composed of a single layer of carbon atoms – is more likely to become a superconductor than originally thought possible.
"Graphene by itself can conduct energy, as a normal metal is conductive, but it is only recently that we learned it can also be a superconductor, by making a so-called 'magic angle' – twisting a second layer of graphene on top of the first," said Jeanie Lau, a professor of physics at Ohio State and lead author of the paper. "And that opens possibilities for additional research to see if we can make this material work in the real world."
Unlike most conventional conductors, superconductors are metals that can conduct electricity without resistance, thus suffering no loss of energy.
Graphene is a two-dimensional crystal – a perfectly flat piece of carbon – and as a single layer is not a superconductor. But earlier this year, scientists at the Massachusetts Institute of Technology published research that showed graphene could become a superconductor if one piece of graphene were laid on top of another piece and the layers twisted to a specific angle – what they termed ‘the magic angle’ (see Graphene superlattice can behave like an insulator and a superconductor).
That magic angle, scientists thought, was between 1° and 1.2° – a very precise angle. "The question is, the magic angle, how magic does it have to be?" said Emilio Codecido, a graduate student in Lau's lab and a co-author of the paper.
The Ohio State team found that the magic angle appears to be less magical than originally thought, with graphene layers still superconducting at a smaller angle, around 0.9°. It is a small distinction, but it could open the possibility of new experiments to investigate graphene as a potential superconductor in the real world. So far, superconducting is limited outside of scientific laboratories, because in order to superconduct electricity, the electric lines must be kept at extremely low temperatures.
"This research pushed our understanding of superconductors and the magic angle a little further than the theory and prior experiments might have expected," said Marc Bockrath, a co-author of the paper and a physics professor at Ohio State.
"Superconductivity could revolutionize many industries – electric transmission lines, communication lines, transportation, trains," Codecido said. "Superconductivity in twisted bilayer graphene will teach us about superconductivity at much higher temperatures, temperatures that will be useful for real-world applications. That's where future work will be focused."
This story is adapted from material from Ohio State University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.