Condensed Matter Seminar

Michael Zudov
University of Minnesota

Tuesday, January 13, 2009; 4:00 pm in JFB 334

Temperature dependence of microwave-induced resistance oscillations in high-mobility 2D electron systems

When a high quality two-dimensional electron system is irradiated by microwaves, its magnetoresistance exhibits pronounced microwave-induced resistance oscillations (MIRO) and zero-resistance states. MIRO were theoretically discussed in terms of the "displacement" model, which is based on microwave-assisted impurity scattering, and the "inelastic" model, stepping from the oscillatory electron distribution function. It has been argued that the "inelastic" contribution greatly exceeds the "displacement" contribution and accounts for MIRO temperature dependence. This talk will discuss our recent experiments focusing on the temperature dependence of MIRO. We find that the MIRO amplitude decays exponentially with increasing temperature, as exp(-&alpha T²), where &alpha scales with the inverse magnetic field. This observation suggests that in our high-mobility sample the temperature dependence originates primarily from the modification of the single particle lifetime, which we attribute to electron-electron interaction effects, and that the "displacement" contribution remains relevant under typical experimental conditions.