Imaging coherent transport in graphene (part I): mapping universal conductance fluctuations
- 22 June 2010
- journal article
- Published by IOP Publishing in Nanotechnology
- Vol. 21 (27), 274013
- https://doi.org/10.1088/0957-4484/21/27/274013
Abstract
Graphene provides a fascinating testbed for new physics and exciting opportunities for future applications based on quantum phenomena. To understand the coherent flow of electrons through a graphene device, we employ a nanoscale probe that can access the relevant length scales--the tip of a liquid-He-cooled scanning probe microscope (SPM) capacitively couples to the graphene device below, creating a movable scatterer for electron waves. At sufficiently low temperatures and small size scales, the diffusive transport of electrons through graphene becomes coherent, leading to universal conductance fluctuations (UCF). By scanning the tip over a device, we map these conductance fluctuations versus scatterer position. We find that the conductance is highly sensitive to the tip position, producing delta G approximately e(2)/h fluctuations when the tip is displaced by a distance comparable to half the Fermi wavelength. These measurements are in good agreement with detailed quantum simulations of the imaging experiment and demonstrate the value of a cooled SPM for probing coherent transport in graphene.This publication has 34 references indexed in Scilit:
- Origin of spatial charge inhomogeneity in grapheneNature Physics, 2009
- Spatially resolved spectroscopy of monolayer graphene onPhysical Review B, 2009
- Observation of electron–hole puddles in graphene using a scanning single-electron transistorNature Physics, 2007
- Scattering and Interference in Epitaxial GrapheneScience, 2007
- High-resolution scanning tunneling microscopy imaging of mesoscopic graphene sheets on an insulating surfaceProceedings of the National Academy of Sciences of the United States of America, 2007
- Energy Band-Gap Engineering of Graphene NanoribbonsPhysical Review Letters, 2007
- Room-Temperature Quantum Hall Effect in GrapheneScience, 2007
- The rise of grapheneNature Materials, 2007
- Imaging Coherent Electron Flow from a Quantum Point ContactScience, 2000
- Subsurface charge accumulation imaging of a quantum Hall liquidNature, 1998