Graphene

Research

The study of graphene, a single atomic layer of carbon atoms arranged in a honeycomb lattice, has become an extraordinarily active area of research since the first flakes were experimentally realized in 2004. Early measurements have revealed unique electronic characteristics and high sample quality, a combination that promises applicability across multiple fields, ranging from carbon electronics to chemical sensing to quantum electrodynamics. In our lab, we have achieved exceptionally high sample quality by both suspending the graphene flakes, as well as encapsulating them with hBN. We have used transport techniques, as well as a scanning SET to probe exciting new physics in this material.

We have active collaborations with the Kim Group at Harvard and the Jarillo-Herrero Group at MIT.

Selected research:

Oscillations in conductance arising from a Mach-Zehnder interferometer created at a PN junction in graphene. D.S. Wei et al. Science Advances Vol. 3, no.8 (2017) For a talk given on this work, please see: Princeton Center for Theoretical Science.

(Kim Group) False colour scanning electron microscopy (SEM) image of device to measure superconducting correlations in a quantum Hall edge. G.H. Lee et al. Nature Physics 13 693-698 (2017)

 

Bilayer graphene device on hexagonal Boron nitride, used to study the fractional quantum Hall effect. Both integer and fractional Landau Levels show electron-hole asymmetry. A. Kou et al. Science 345 6192 (2014).

Landau fan of monolayer graphene showing an unconventional fractional quantum Hall sequence. Measurement is done using a scanning Single Electron Transistor (SET), about 100nm in size. B. Feldman et al. Science 337 1196-1199 (2012).

 

Colour map of electron and hole puddles of graphene on an SiO2/Si substrate. J. Martin et al. Nature Physics 4 (February 2008).

SEM image (false color) of a doubly gated, suspended graphene bilayer. The graphene flake (red) is contacted by metal leads (yellow) which allow for transport measurements to be performed. T. Weitz et al. Science 330 812-816 (2010).