Graphene: New electronic state discovered

The LCN team have found electronic stripes called 'charge density waves' on the surface of graphene sheets that make up a graphitic superconductor. This is the first time these stripes have been seen on graphene, a material that looks set to play a key role in the future of nanotechnology. The researchers donated extra electrons to a graphene surface by sliding calcium metal atoms underneath it. Normally, additional electrons would spread out evenly on the graphene surface, but by using a scanning tunnelling microscope, which can image individual atoms, the team found that the extra electrons arranged themselves spontaneously into nanometre scale stripes. According to the LCN, this unexpected behaviour demonstrates that the electrons can have a life of their own which is not connected directly to the underlying atoms. The findings could pave the way for a new method of manipulating and coding information, where binary zeros and ones correspond to stripes running from north to south and from east to west respectively. Professor Jan Zaanen of Leiden University, who has been working on the project, said: "This discovery is another important step towards demonstrating the ubiquity of stripes and the fact that they appear in the world's simplest host – the two dimensional network of carbon atoms that is graphene – means that more great science and applications are not far behind." The research is part of an ongoing multidisciplinary research effort into graphene at the LCN and is published in Nature Physics.