Understanding resonant charge transport through weakly coupled single-molecule junctions

Journal article

Off-resonant charge transport through molecular junctions has been extensively studied since the advent of single-molecule electronics and it is now well understood within the framework of the non-interacting Landauer approach. Conversely, gaining a qualitative and quantitative understanding of the resonant transport regime has proven more elusive. Here, we study resonant charge transport through graphene-based zinc-porphyrin junctions. We experimentally demonstrate an inadequacy of the non-interacting Landauer theory as well as the conventional single-mode Franck-Condon model. Instead, we model the overall charge transport as a sequence of non-adiabatic electron transfers, the rates of which depend on both outer and inner-sphere vibrational interactions. We show that the transport properties of our molecular junctions are determined by a combination of electron-electron and electron-vibrational coupling, and are sensitive to the interactions with the wider local environment. Furthermore, we assess the importance of nuclear tunnelling and examine the suitability of semi-classical Marcus theory as a description of charge transport in molecular devices.

Authors: Thomas, JO; Limburg, B; Sowa, JK; Willick, K; Baugh, J

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Springer Nature
• Journal: Nature Communications
• Volume: 10
• Article number: 4628
• Publication date: 2019-10-11
• Acceptance date: 2019-09-20
• DOI: 10.1038/s41467-019-12625-4
• EISSN: 2041-1723
• Keywords: physics.chem-ph; cond-mat.mes-hall