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UID:UW-Physics-Event-1690
DTSTART:20100311T160000Z
DURATION:PT1H0M0S
DTSTAMP:20260422T131502Z
LAST-MODIFIED:20100226T200803Z
LOCATION:5310 Chamberlin
SUMMARY:Theory of nonequilibrium magnetooscillations in 2D electron tr
 ansport in high Landau levels\, R. G. Herb Condensed Matter Seminar\, 
 Ivan Dmitriev\, Institute for Theoretical Physics\, Karlsruhe Universi
 ty\, Germany
DESCRIPTION:We propose a unified quantum kinetic description of a fami
 ly of nonequilibrium magnetooscillations recently discovered in high-m
 obility quantum Hall structures\, including the microwave induced resi
 stance oscillations (MIRO)\, Hall-field induced RO (HIRO)\, and phonon
  induced RO (PIRO). The magnetoresistivity is due to quantum oscillati
 ons in the density of states in high Landau levels and is governed by 
 spectral and spatial resonances set by the cyclotron frequency and the
  cyclotron diameter in various combinations with the parameters of the
  external fields and phonons. External ac or dc driving leads to local
  population inversion in the energy distribution of electrons and modi
 fies the scattering off impurities and phonons. In particular\, PIRO a
 re shown to be very sensitive to the applied direct current.  In the s
 upersonic regime\, where the Hall velocity exceeds the sound velocity\
 , the phonon-assisted conductivity remains finite at zero temperature\
 , while below the supersonic transition the oscillations get exponenti
 ally suppressed at low temperature. Quite interestingly\, in the micro
 wave-illuminated inhomogeneous 2D electron gas\, the photocurrent and 
 photovoltage oscillations arise in the absence of the external dc driv
 ing\, due to nonequilibrium violation of the Einstein relation between
  electrical current and diffusion. <br>
\n<br>
\n[ I.A. Dmitriev et al
 .\, PRL 91\, 226802 (2003)\; 99\, 206805 (2007)\; JETP Lett. 85\, 86 (
 2007)\; PRB 70\, 165305 (2004)\; 71\, 115316 (2005)\; 75\, 245320 (200
 7)\; 80\, 125418 (2009)\; 80\, 165327 (2009).]
URL:https://www.physics.wisc.edu/events/?id=1690
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