Dresden 2003 – scientific programme
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TT: Tiefe Temperaturen
TT 22: Metall-Isolator-Überg
änge in Quantensystemen II
TT 22.4: Talk
Friday, March 28, 2003, 11:00–11:15, HSZ301
Optically induced coherent voltage oscillations in blue bronze — •B. Beschoten1, I. Dotsenko1, P.H.M. van Loosdrecht2, and S. van Smaalen3 — 12. Physikalisches Institut, RWTH Aachen, 52056 Aachen, Germany — 2Material Science Center, University of Groningen, The Netherlands — 3Lehrstuhl fur Kristallographie, Universität Bayreuth, Germany
The fundamental mode of conduction in charge density wave (CDW) systems is the collective translational motion of the CDW condensate, leading to highly non-linear transport properties. One of the most striking transport phenomena observed in some CDW materials are the so-called No-dqnarrow band noiseNo-dq oscillations. These are coherent oscillations of the voltage response to a DC current, presumably resulting from a combination of pinning and periodic charging. In this contribution we report on a temperature and energy dependent study of the non-linear charge transport in blue bronze, focusing on the occurrence of coherent oscillations. In particular it will be shown that, using short tunable infrared pulses (FELIX free electron laser), one can optically induce the coherent oscillations lasting for several milliseconds. The frequency of the observed oscillations (observed in time-domain transient optical pump-voltage probe experiments) varies from less than 1 Hz upto several hundred KHz, depending on the applied DC current, and persist up to several tens of kelvin. Work supported by DFG through SPP 1073, grant nos. LO 715/1-1, BE 2441/1-1, and SM 55/6-2, by Dutch Foundation for Fundamental Research on Matter, and by TMR ’Access to large-scale facilities’ programme of the EC.