title: Local transport measurements at mesoscopic length scales using scanning tunneling potentiometry.
abstract: Under mesoscopic conditions, the transport potential on a thin film carrying a current is theoretically expected to bear spatial variation due to quantum interference. Scanning tunneling potentiometry is the ideal tool to investigate such variation, by virtue of its high spatial resolution. We report in this Letter the first detailed measurement of transport potential under mesoscopic conditions. Epitaxial graphene at a temperature of 17 K was chosen as the initial system for study because the characteristic transport length scales in this material are relatively large. Tip jumping artifacts are a major possible contribution to systematic errors; and we mitigate such problems by using custom-made slender and sharp tips manufactured by focused ion beam. In our data, we observe residual resistivity dipoles associated with topographical defects, and local peaks and dips in the potential that are not associated with topographical defects.
authors.affiliation: Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA.
authors.forename: Weigang
authors.initials: W
authors.lastname: Wang
authors.affiliation: Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA.
authors.forename: Ko
authors.initials: K
authors.lastname: Munakata
authors.affiliation: Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Rozler
authors.affiliation: Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA.
authors.forename: Malcolm R
authors.initials: MR
authors.lastname: Beasley