2011/08/18 by Mikkel Strange, Strange, M., Kristian S. Thygesen +1
Engineering · Physics and Astronomy · #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Molecular Junctions and Nanostructures #Quantum and electron transport phenomena #Surface and Thin Film Phenomena
paper · pdf · doi:10.48550/arxiv.1108.3687
openalex publication_date 2011/08/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The calculation of electronic conductance of nano-scale junctions from first principles is a long standing problem in molecular electronics. Here we demonstrate excellent agreement with experiments for the transport properties of the gold/alkanediamine benchmark system when electron-electron interactions are described using the many-body GW approximation. The main difference from standard density functional theory (DFT) calculations is a significant reduction of the contact conductance, Gc, due an improved alignment of the molecular energy levels with the metal Fermi energy. The molecular orbitals involved in the tunneling process comprise states delocalized over the carbon backbone and states localized on the amine end groups. We find that dynamical screening effects renormalize the two types of states in qualitatively different ways when the molecule is inserted in the junction. Consequently, the GW transport results cannot be mimicked by DFT calculations employing a simple scissors operator.