Modeling the Electrostatic Potential Spatial Profile of Molecular Junctions

A bstract : The spatial profile of the electrostatic potential across a molecular junction is one of the single most influential factors in determining the form of intensity‐voltage characteristics. We have modeled the influence of bridge electronic defects (site substitutions) and weak links (local weak bonds) on the potential profile. The potential is determined self‐consistently by solving Poisson and Schrödinger equations simultaneously. We have considered the simplest model of a one‐dimensional molecular wire. This system already exhibits some of the most relevant features observed in I‐V curves of real chemically modified junctions, where strong asymmetries and rectification effects have been reported.