# Imaging Coherent Transport in Graphene (Part I): Mapping Universal Conductance Fluctuations

 Title: Imaging Coherent Transport in Graphene (Part I): Mapping Universal Conductance Fluctuations Author: Berezovsky, Jesse; Borunda, Mario; Heller, Eric J.; Westervelt, Robert M. Note: Order does not necessarily reflect citation order of authors. Citation: Berezovsky, Jesse, Mario Borunda, Eric J. Heller, and Robert M. Westervelt. 2010. Quantum Science and Technology at the Nanoscale. Special Issue. Nanotechnology 21(27): 274013. Full Text & Related Files: Berezovsky_Imaging.pdf (2.009Mb; PDF) 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 $$\delta G \sim e^2/h$$ 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. Published Version: doi:10.1088/0957-4484/21/27/274013 Terms of Use: This article is made available under the terms and conditions applicable to Open Access Policy Articles, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#OAP Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:5364421

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