title: Electronic transport on the nanoscale: ballistic transmission and Ohm's law.
abstract: If a current of electrons flows through a normal conductor (in contrast to a superconductor), it is impeded by local scattering at defects as well as phonon scattering. Both effects contribute to the voltage drop observed for a macroscopic complex system as described by Ohm's law. Although this concept is well established, it has not yet been measured around individual defects on the atomic scale. We have measured the voltage drop at a monatomic step in real space by restricting the current to a surface layer. For the Si(111)-( [see text]3 x [see text]3)-Ag surface a monotonous transition with a width below 1 nm was found. A numerical analysis of the data maps the current flow through the complex network and the interplay between defect-free terraces and monatomic steps.
authors.affiliation: Physikalisches Institut, University of Gottingen, Gottingen, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Homoth
authors.forename: M
authors.initials: M
authors.lastname: Wenderoth
authors.forename: T
authors.initials: T
authors.lastname: Druga
authors.forename: L
authors.initials: L
authors.lastname: Winking
authors.forename: R G
authors.initials: RG
authors.lastname: Ulbrich
authors.forename: C A
authors.initials: CA
authors.lastname: Bobisch
authors.forename: B
authors.initials: B
authors.lastname: Weyers
authors.forename: A
authors.initials: A
authors.lastname: Bannani
authors.forename: E
authors.initials: E
authors.lastname: Zubkov
authors.forename: A M
authors.initials: AM
authors.lastname: Bernhart
authors.forename: M R
authors.initials: MR
authors.lastname: Kaspers
authors.forename: R
authors.initials: R
authors.lastname: Möller