•Maya Schöck1, Svenja Klages1, Christoph
Sürgers1 und Hilbert v. Löhneysen1,2
1Physikalisches Institut und DFG Center for Functional Nanostructures,
Universität Karlsruhe, D-76128 Karlsruhe
2Forschungszentrum Karlsruhe, Institut für Festkörperphysik,
D-76021 Karlsruhe
Chainlike surface structures are observed after evaporation of submonolayer coverages of Au on Si(111) miscut by 10° towards the < [`1][`1]2 > direction. This Si(557):Au surface is controversally discussed due to its unusual electronic properties found in various angular resolved photoemission spectroscopy experiments.
In this work, scanning tunneling microscopy and spectroscopy have been
performed to investigate the local structural and electronic properties
of this surface. Tunneling spectra taken on or off the distinct chainlike
structures exhibit strong differences due to the lateral variation of the
local surface density of states. The spectra are compared to recent theoretical
band-structure calculations. In addition, electronic transport measurements
have been performed in situ for temperatures T = 1.8 - 300
K. In all cases studied, the electrical resistance measured with the current
running along the chainlike structures exhibits an increase with decreasing
temperature, i.e. non-metallic behaviour is found. Several possible reasons
for this behaviour, such as activated hopping between segments of chains,
are discussed.