Low-Temperature Conductance Measurements On Single Molecules

•Joachim Reichert1, Heiko B. Weber1, Marcel Mayor1 und Hilbert von Löhneysen2
1Forschungszentrum Karlsruhe, Institut für Nanotechnologie, Postfach 3640, D-76021 Karlsruhe
2Physikalisches Institut, Universität Karlsruhe, D-76128 Karlsruhe and Forschungszentrum Karlsruhe, Institut für Festkörperphysik, D-76021 Karlsruhe

We present an experimental protocol which allows to perform conductance spectroscopy on single organic molecules at low temperatures (T » 30K) [1]. The conductance data obtained at low-T with a conjugated sample molecule show a highly improved data quality with a higher stability, narrower linewidth and substantially reduced noise compared to room-temperature (RT) data [2]. For the RT measurements a rather broad range of sample-to-sample fluctuations was attributed to different microscopic contact realisations. The smaller number of variations in the recorded low-T spectra might indicate that here energetically favourable configurations occure more frequently. Thus the comparability of experimental data with other experiments as well as with theoretical simulations is considerably improved.