Berlin 2015 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 107: Microcavities, polaritons and condensates
HL 107.1: Talk
Friday, March 20, 2015, 10:15–10:30, EW 015
Optical bistability in electrically driven polariton condensates — •Matthias Amthor1, Timothy Liew2, Christian Metzger1, Sebastian Brodbeck1, Martin Kamp1, Ivan Shelykh2,3, Alexey Kavokin4,5, Christian Schneider1, and Sven Höfling1,6 — 1Technische Physik and Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems, Universität Würzburg, D-97074 Würzburg, Am Hubland, Germany. — 2Division of Physics and Applied Physics, Nanyang Technological University 637371, Singapore. — 3Science Institute, University of Iceland, Dunhagi 3, IS-107, Reykjavik, Iceland. — 4Spin Optics Laboratory, St-Petersburg State University, 1, Ulianovskaya, St.-Petersburg, 198504, Russia. — 5Physics and Astronomy School, University of Southampton, Highfield, Southampton, SO171BJ, UK. — 6School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, UK.
We observe a bistability in an electrically driven polariton condensate, which is manifested by a memory dependent threshold characteristic. In contrast to the polariton bistabilities previously observed, our effect occurs under non-resonant electric pumping and is triggered by the current injection scheme. We explain the origin of the bistability by a dependence of the electron-hole tunneling lifetime on the carrier density in the embedded QWs. The field screening effect creates a positive feedback loop, which yields the bistable behavior of the condensate. We develop a rate-equation based model which qualitatively explains the occurrence of the hysteresis, its reduction with increased magnetic field, and the absence of bistability under optical pumping.