Effects of stochastic fluctuations at molecule-electrode contacts in transition voltage spectroscopy

• Verfasst von: Bâldea, Ioan [VerfasserIn]
• Titel: Effects of stochastic fluctuations at molecule-electrode contacts in transition voltage spectroscopy
• Verf.angabe: Ioan Bâldea
• E-Jahr: 2012
• Jahr: 1 March 2012
• Umfang: 7 S.
• Fussnoten: Available online 1 March 2012 ; Gesehen am 02.08.2018
• Titel Quelle: Enthalten in: Chemical physics
• Ort Quelle: Amsterdam [u.a.] : Elsevier Science, 1973
• Jahr Quelle: 2012
• Band/Heft Quelle: 400(2012), Seite 65-71
• DOI: doi:10.1016/j.chemphys.2012.02.011
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: Break junctions
• Sach-SW: Conductance histograms
• Sach-SW: Fowler-Nordheim transition
• Sach-SW: Molecular electronics
• Sach-SW: Transition voltage spectroscopy
• K10plus-PPN: 1578218179

Abstract

The influence of the stochastic fluctuations at contacts on the electron transport through molecular junctions based on alkanedithiols is investigated theoretically. Results are presented, which demonstrate that the transition voltage Vt is insensitive to fluctuations in the electrode-molecule hopping integrals. By contrast, reasonably large fluctuations (δJ∼2eV) in the Coulomb contact interaction J, included via an extended Newns-Anderson model, lead to fluctuations in the molecular orbital energetic alignment ε0, which are consistent with the fluctuations in Vt observed experimentally. The impact of these J- (or ε0-) fluctuations on the conductance G is considerably stronger than on Vt. The G-fluctuations driven by δJ represent a substantial fraction of the fluctuations displayed by experimental conductance histograms. The electron system for J≠0 is correlated, i.e., it cannot be described within a single-particle (Landauer-based) picture. However, in the J-range of interest, the ratio Vt/ε0 turns out to be only weakly dependent on J. The weak impact of J on the ratio Vt/ε0 is important because it suggests that, even in the presence of realistically strong electron correlations, transition voltage spectroscopy can be a useful tool of investigation.