Abstract:
Charge transport in nanoscale systems such as molecules has long been a topic of intense study due to the quantum character of their transport. This leads to unique quantum phenomena in molecule-sized devices that are not observed in traditional electronics. For example, in a traditional electronic resistor, conductance is expected to decay as the device length increases. For some molecular resistor series, it has been demonstrated that conductance can instead increase with molecular/device length. This idea has been called both reversed conductance decay and anti-ohmic conductance. While such reversals of conductance decay have been repeatedly theoretically predicted, they have only rarely been confirmed experimentally. Previous studies have suggested that theoretical multi-reference(static) electron correlation errors may be an important cause of this discrepancy, yet most single-molecule transport methods are unable to treat multireference electron correlation. To address this issue, we developed a new approach for the study of single-molecule transport systems denoted NEGF-MCPDFT, which combines multiconfiguration pair-density functional theory (MC-PDFT) with non-equilibrium Green’s functions (NEGF). NEGF-MCPDFT allows for the efficient inclusion of both static and dynamic electron correlations in the description of the electronic structure while still supporting a similar electrode description as traditional single-reference NEGF methods. In this presentation, we outline the development of the NEGF-MCPDFT methodology and discuss the impact of electron correlation on molecular charge transport and quantum phenomena in nanoelectronics.