Observation of a cyclotron harmonic spike in microwave-induced resistances in ultraclean GaAs/AlGaAs quantum wells

We report the observation of a colossal, narrow resistance peak that arises in ultraclean (mobility ∼3×10⁷ cm²/V s) GaAs/AlGaAs quantum wells (QWs) under millimeter wave irradiation and a weak magnetic field. Such a spike is superposed on the 2nd harmonic microwave-induced resistance oscillations (M...

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Bibliographic Details
Published inPhysical review letters Vol. 105; no. 24; p. 246802
Main Authors Dai, Yanhua, Du, R R, Pfeiffer, L N, West, K W
Format Journal Article
LanguageEnglish
Published United States 10.12.2010
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Summary:We report the observation of a colossal, narrow resistance peak that arises in ultraclean (mobility ∼3×10⁷ cm²/V s) GaAs/AlGaAs quantum wells (QWs) under millimeter wave irradiation and a weak magnetic field. Such a spike is superposed on the 2nd harmonic microwave-induced resistance oscillations (MIRO) but having an amplitude >300% of the MIRO, and a typical FWHM ∼50 mK, comparable with the Landau level width. Systematic studies show a correlation between the spike and a pronounced negative magnetoresistance in these QWs, suggesting a mechanism based on the interplay of strong scatterers and smooth disorder. Alternatively, the spike may be interpreted as a manifestation of quantum interference between the quadrupole resonance and the higher-order cyclotron transition in well-separated Landau levels.
ISSN:1079-7114
DOI:10.1103/PhysRevLett.105.246802