The scanning single-electron transistor (SET) microscope head, seen through a viewport into the microscope vacuum chamber. The image shows the SET tip above a graphene sample. (Courtesy: Yacoby lab)
Graphene offers up another quantum surprise
Physicists in the US and Germany have discovered yet another surprising property of the “wonder material” graphene – it displays a fractional quantum Hall effect (FQHE) that is different to that seen in conventional materials. The finding will be important for studying correlations among relativistic particles and may even help in the development of quantum computers in the future.
The FQHE occurs when charge carriers like electrons are confined to a 2D plane, as in graphene, and are subjected to a perpendicular magnetic field in the Z-direction. If a current flows in the X-direction, a voltage – the Hall voltage – occurs in the Y-direction. At very low temperatures, this voltage is quantized in distinct steps or Hall states.