A team led by researchers from Harvard University and the University of Maryland in the US has used defects in diamond to map the magnetic field generated by electrical currents in graphene. Their experiments reveal that currents in this atomically-thin form of carbon flow like a viscous fluid – a result that could provide fresh insights into the collective behaviour of electrons in strongly-interacting quantum systems.
Graphene has many exceptional electrical properties. Among them is the fact that, at the point where its conduction and valence bands just touch each other (the Dirac point), it can support currents composed of electrons and an equal number of positively-charged holes, rather than electrons alone. In the present work, Ronald Walsworth, Amir Yacoby and colleagues set out to establish whether these electron-hole plasmas (or Dirac fluids, as they are also known) flow smoothly, like electrons travelling through a metallic wire, or unevenly like water running through a pipe.
To read more, click here.