title: Coherently driven, ultrafast electron-phonon dynamics in transport junctions.
abstract: Although the vast majority of studies of transport via molecular-scale heterojunctions have been conducted in the (static) energy domain, experiments are currently beginning to apply time domain approaches to the nanoscale transport problem, combining spatial with temporal resolution. It is thus an opportune time for theory to develop models to explore both new phenomena in, and new potential applications of, time-domain, coherently driven molecular electronics. In this work, we study the interaction of a molecular phonon with an electronic wavepacket transmitted via a conductance junction within a time-domain model that treats the electron and phonon on equal footing and spans the weak to strong electron-phonon coupling strengths. We explore interference between two coherent energy pathways in the electronic subspace, thus complementing previous studies of coherent phenomena in conduction junctions, where the stationary framework was used to study interference between spatial pathways. Our model provides new insights into phase decoherence and population relaxation within the electronic subspace, which have been conventionally treated by density matrix approaches that often rely on phenomenological parameters. Although the specific case of a transport junction is explored, our results are general, applying also to other instances of coupled electron-phonon systems.
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Joshua E
authors.initials: JE
authors.lastname: Szekely
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Tamar
authors.initials: T
authors.lastname: Seideman