Graphene Doping Reaches New Levels

Graphene is famous for its peculiar electronic properties exemplified by the Dirac point, a region in the material’s band structure where electron behavior resembles that of high-energy particles. An electron carrying charge through graphene in a Dirac-like fashion acts like a single particle that barely interacts with its many peers. Now, Philipp Rosenzweig and his colleagues from the Max Planck Institute for Solid State Research in Germany, have added an excessive amount of charge carriers to graphene [1], moving the material away from said Dirac point to a Van Hove point and, reportedly for the first time, even beyond. The Van Hove point features a large number of states, which gives charge carriers ample opportunity to interact, conspire, and form collective states of matter, such as magnetism and superconductivity. Such collective states cannot be described in a single-particle picture. Excitingly, theoretical predictions for doped graphene include exotic states, like high-temperature chiral topological superconductivity [2], which can now be explored with the controllable doping techniques demonstrated by Rosenzweig and colleagues.