Imaging Electron Flow through Graphene Point Contacts

Cooled scanning gate microscopy is used to image the flow of electrons through graphene point contacts. Point contacts in 2-dimensional materials are known to be useful to understanding mesoscopic physics, and generally exhibit conductance quantization of 2πe²/h. However, observation of conductance quantization in graphene often proves challenging. Using a charged scanning probe tip to manipulate the motion of electrons in graphene, we will map conductance as a function of back gate voltage in order to better understand the causes behind this challenge.