title: Image effects in transport at metal-molecule interfaces.
abstract: We present a method for incorporating image-charge effects into the description of charge transport through molecular devices. A simple model allows us to calculate the adjustment of the transport levels, due to the polarization of the electrodes as charge is added to and removed from the molecule. For this, we use the charge distributions of the molecule between two metal electrodes in several charge states, rather than in gas phase, as obtained from a density-functional theory-based transport code. This enables us to efficiently model level shifts and gap renormalization caused by image-charge effects, which are essential for understanding molecular transport experiments. We apply the method to benzene di-amine molecules and compare our results with the standard approach based on gas phase charges. Finally, we give a detailed account of the application of our approach to porphyrin-derivative devices recently studied experimentally by Perrin et al. [Nat. Nanotechnol. 8, 282 (2013)], which demonstrates the importance of accounting for image-charge effects when modeling transport through molecular junctions.
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands.
authors.forename: C J O
authors.initials: CJ
authors.lastname: Verzijl
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands.
authors.forename: J A
authors.initials: JA
authors.lastname: Celis Gil
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands.
authors.forename: M L
authors.initials: ML
authors.lastname: Perrin
authors.affiliation: Departamento de Física, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago de Chile, Chile.
authors.forename: D
authors.initials: D
authors.lastname: Dulić
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands.
authors.forename: H S J
authors.initials: HS
authors.lastname: van der Zant
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands.
authors.forename: J M
authors.initials: JM
authors.lastname: Thijssen