  Atomic-scale charge transport properties are not only of significant
fundamental interest but also highly relevant for numerous technical
applications. However, experimental methods which are capable of detecting
charge transport at the relevant single-digit nanometer length scales are
scarce. Here we report on molecular nanoprobe (MONA) experiments on Pd(110)
where we utilize the charge carrier-driven switching of a single cis-2-butene
molecule to detect ballistic transport properties over length scales of a few
nanometers. Our data demonstrate a striking angular dependence with a dip in
charge transport along the [1-10]-oriented atomic rows and a peak in the
transverse [001] direction. The narrow angular width of both features and
distance-dependent measurements suggest that the nanometer-scale ballistic
transport properties of metallic surfaces is significantly influenced by the
atomic structure.
