Abstract
We look for manifestations of quantum interference effects in the Seebeck coefficient of a molecular junction, when the electronic conductance exhibits pronounced destructive interference features due to the presence of quasi-degenerate electronic states, which differ in their spatial symmetry. We perform our analysis by considering three separate limits for electron transport: coherent, fully dephased, and suffering inelastic scattering with molecular vibrations. We find that in the considered geometry, although the conductance displays strong signatures of the underlying transport mechanisms—destructive quantum interference features in the coherent case and thermal activation characteristics in the inelastic limit—the Seebeck coefficient conceals details of electron dynamics, whereas it robustly reveals information about the energy characteristics of the junction. It should be emphasized that in other geometries (e.g., when a transmission node develops close to the Fermi energy), the Seebeck coefficient may show different features, potentially exposing the underlying dynamics. We provide closed-form expressions for the electronic conductance and the thermopower of our system as a function of temperature, gate voltage, and hybridization energy in different transport limits, and we then exemplify our analysis on a specific conjugated molecule with quasi-degenerate orbitals of different spatial symmetry.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.