Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 3: Transport: Quantum Dots, Quantum Wires, Point Contacts

TT 3.3: Vortrag

Montag, 20. März 2017, 10:00–10:15, HSZ 201

Franck-Condon blockade in driven quantum dots — Patrick Haughian¹, Stefan Walter², Andreas Nunnenkamp³, and •Thomas Schmidt¹ — ¹Physics and Materials Science Research Unit, University of Luxembourg, 1511 Luxembourg, Luxembourg — ²Institute for Theoretical Physics, University Erlangen-Nurnberg, Staudtstraße 7, 91058 Erlangen, Germany — ³Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE, United Kingdom

Electron-vibron coupling in quantum dots can lead to a strong suppression of the average current in the sequential tunneling regime. This effect is known as Franck-Condon blockade and can be traced back to an overlap integral between vibron states with different electron numbers which becomes exponentially small for large electron-vibron coupling strength. Here, we investigate the effect of a time-dependent drive on this phenomenon, in particular the effect of an oscillatory gate voltage acting on the electronic dot level. We find that the drive can lift the blockade by exciting vibrons. As a consequence, the relative change in average current grows exponentially with the drive strength. We show that this exponential response to a small drive amplitude has important consequences for charge pumping in Franck-Condon blockaded quantum dots.