title: Current rectification in a single molecule diode: the role of electrode coupling.
abstract: We demonstrate large rectification ratios (> 100) in single-molecule junctions based on a metal-oxide cluster (polyoxometalate), using a scanning tunneling microscope (STM) both at ambient conditions and at low temperature. These rectification ratios are the largest ever observed in a single-molecule junction, and in addition these junctions sustain current densities larger than 10(5) A cm(-2). By following the variation of the I-V characteristics with tip-molecule separation we demonstrate unambiguously that rectification is due to asymmetric coupling to the electrodes of a molecule with an asymmetric level structure. This mechanism can be implemented in other type of molecular junctions using both organic and inorganic molecules and provides a simple strategy for the rational design of molecular diodes.
authors.affiliation: Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanoscience), Faraday, 9, Ciudad Universitaria de Cantoblanco, 28049, Madrid, Spain. Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Facultad de Ciencias, c/ Francisco Tomás y Valiente, 7 Universidad Autónoma de Madrid 28049 Madrid, Spain.
authors.forename: Siya
authors.initials: S
authors.lastname: Sherif
authors.forename: Gabino
authors.initials: G
authors.lastname: Rubio-Bollinger
authors.forename: Elena
authors.initials: E
authors.lastname: Pinilla-Cienfuegos
authors.forename: Eugenio
authors.initials: E
authors.lastname: Coronado
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Cuevas
authors.forename: Nicolás
authors.initials: N
authors.lastname: Agraït