Charge transport in single Au / alkanedithiol / Au junctions: coordination geometries and conformational degrees of freedom.
Recent STM molecular break-junction experiments have revealed multiple series of peaks in the conductance histograms of alkanedithiols. To resolve a current controversy, we present here an in-depth study of charge transport properties of Au|alkanedithiol|Au junctions. Conductance histograms extracted from our STM measurements unambiguously confirm features showing more than one set of junction configurations. On the basis of quantum chemistry calculations, we propose that certain combinations of different sulfur-gold couplings and trans/gauche conformations act as the driving agents. The present study may have implications for experimental methodology: whenever conductances of different junction conformations are not statistically independent, the conductance histogram technique can exhibit a single series only, even though a much larger abundance of microscopic realizations exists.
Li
Chen
C
Institute of Bio- and Nanosystems IBN 3 and Center of Nanoelectronic Systems for Information Technology, Research Center Jülich, D-52425 Jülich, Germany.
Pobelov
Ilya
I
Wandlowski
Thomas
T
Bagrets
Alexei
A
Arnold
Andreas
A
Evers
Ferdinand
F
D004553:Electric Conductivity; D006046:Gold / Q000737:chemistry*; D008968:Molecular Conformation; D011789:Quantum Theory; D013438:Sulfhydryl Compounds / Q000737:chemistry*
D013438:Sulfhydryl Compounds; D006046:Gold