Eur. Phys. J. B (2012) 85: 316
https://doi.org/10.1140/epjb/e2012-30407-5

Regular Article

Vibration induced memory effects and switching in ac-driven molecular nanojunctions

Institute of Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany

^a e-mail: andrea.donarini@physik.uni-regensburg.de

Received: 21 May 2012
Received in final form: 18 July 2012
Published online: 17 September 2012

Abstract

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.