Vibration induced memory effects and switching in ac-driven molecular nanojunctions
Institute of Theoretical Physics, University of
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Received in final form: 18 July 2012
Published online: 17 September 2012
We investigate bistability and memory effects in a molecular junction weakly coupled to metallic leads with the latter being subject to an adiabatic periodic change of the bias voltage. The system is described by a simple Anderson-Holstein model and its dynamics is calculated via a master equation approach. The controlled electrical switching between the many-body states of the system is achieved due to polaron shift and Franck-Condon blockade in the presence of strong electron-vibron interaction. Particular emphasis is given to the role played by the excited vibronic states in the bistability and hysteretic switching dynamics as a function of the voltage sweeping rates. In general, both the occupation probabilities of the vibronic states and the associated vibron energy show hysteretic behaviour for driving frequencies in a range set by the minimum and maximum lifetimes of the system. The consequences on the transport properties for various driving frequencies and in the limit of DC-bias are also investigated.
Key words: Mesoscopic and Nanoscale Systems
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2012