2011/07/28 by Justin P. Bergfield, Bergfield, Justin P., Joshua Barr +3 · 1 citation
Chemistry · Engineering · Physics and Astronomy · #Advanced Physical and Chemical Molecular Interactions #Chemical Physics (physics.chem-ph) #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Molecular Junctions and Nanostructures #Other Condensed Matter (cond-mat.other) #Quantum and electron transport phenomena #Surface and Thin Film Phenomena
paper · pdf · doi:10.48550/arxiv.1107.5854
openalex publication_date 2011/07/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The transport through a quantum-scale device may be characterized by the\ntransmission eigenvalues. These values constitute a junction PIN code where,\nfor example, in single-atom metallic contacts the number of transmission\nchannels is also the chemical valence of the atom. Recently, highly conductive\nsingle-molecule junctions (SMJ) with multiple transport channels have been\nformed from benzene molecules between Pt electrodes. Transport through these\nmulti-channel SMJs is a probe of both the bonding properties at the\nlead-molecule interface and of the molecular symmetry.\n Here we utilize a many-body theory that properly describes the complementary\nnature of the charge carrier to calculate transport distributions through\nPt-benzene-Pt junctions. We develop an effective field theory of interacting\npi-electrons to accurately model the electrostatic influence of the leads and\nan ab initio tunneling model to describe the lead-molecule bonding. With this\nstate-of-the-art many-body technique we calculate the transport using the full\nmolecular spectrum and using an `isolated resonance approximation' for the\nmolecular Green's function.\n We confirm that the number of transmission channels in a SMJ is equal to the\ndegeneracy of the relevant molecular orbital. In addition, we demonstrate that\nthe isolated resonance approximation is extremely accurate and determine that\ntransport occurs predominantly via the HOMO orbital in Pt-benzene-Pt junctions.\nFinally, we show that the transport occurs in a lead-molecule coupling regime\nwhere the charge carriers are both particle-like and wave-like simultaneously,\nrequiring a many-body description.\n