# Imaging Coherent Transport in Graphen (Part II): Probing Weak Localization

 Title: Imaging Coherent Transport in Graphen (Part II): Probing Weak Localization Author: Berezovsky, Jesse; Westervelt, Robert M. Note: Order does not necessarily reflect citation order of authors. Citation: Berezovsky, Jesse and Robert N. Westervelt. 2010. Imaging coherent transport in graphen (part II): probing weak localization. Quantum Science and Technology at the Nanoscale. Special Issue. Nanotechnology 21(27): 274014. Full Text & Related Files: Berezovsky_Imaging_PartII.pdf (2.448Mb; PDF) Abstract: Graphene has opened new avenues of research in quantum transport, with potential applications for coherent electronics. Coherent transport depends sensitively on scattering from microscopic disorder present in graphene samples: electron waves traveling along different paths interfere, changing the total conductance. Weak localization is produced by the coherent backscattering of waves, while universal conductance fluctuations are created by summing over all paths. In this work, we obtain conductance images of weak localization with a liquid-He-cooled scanning probe microscope, by using the tip to create a movable scatterer in a graphene device. This technique allows us to investigate coherent transport with a probe of size comparable to the electron wavelength. Images of magnetoconductance versus tip position map the effects of disorder by moving a single scatterer, revealing how electron interference is modified by the tip perturbation. The weak localization dip in conductivity at $$B=0$$ is obtained by averaging magnetoconductance traces at different positions of the tip-created scatterer. The width $$\Delta B_{WL}$$ of the dip yields an estimate of the electron coherence length $$L_{\phi}$$ fixed charge density. This 'scanning scatterer' method provides a new way of investigating coherent transport in graphene by directly perturbing the disorder configuration that creates these interferometric effects. Published Version: doi:10.1088/0957-4484/21/27/274014 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:5364431 Downloads of this work: