Dresden 2009 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 23: Transport: Nanoelectronics III - Molecular Electronics
TT 23.5: Vortrag
Mittwoch, 25. März 2009, 10:30–10:45, HSZ 105
Charge-memory polaron effect in molecular junctions — •Dmitry A. Ryndyk1, Pino D’Amico1, Gianaurelio Cuniberti2, and Klaus Richter1 — 1Institute for Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany — 2Institute for Material Science and Max Bergmann Center of Biomaterials, Dresden University of Technology, D-01062 Dresden
The charge-memory effect, bistability and switching between charged and neutral states of a molecular junction, as observed in recent STM experiments, is considered within a minimal polaron model. We show that in the case of strong electron-vibron interaction the rate of spontaneous quantum switching between charged and neutral states is exponentially suppressed at zero bias voltage but can be tuned through a wide range of finite switching timescales upon changing the bias. We further find that, while junctions with symmetric voltage drop give rise to random switching at finite bias, asymmetric junctions exhibit hysteretic behavior enabling controlled switching. Lifetimes and charge-voltage curves are calculated by the master equation method for weak coupling to the leads and at stronger coupling by the equation-of-motion method for nonequilibrium Green functions.