title: Superradiant decay of cyclotron resonance of two-dimensional electron gases.
abstract: We report on the observation of collective radiative decay, or superradiance, of cyclotron resonance (CR) in high-mobility two-dimensional electron gases in GaAs quantum wells using time-domain terahertz magnetospectroscopy. The decay rate of coherent CR oscillations increases linearly with the electron density in a wide range, which is a hallmark of superradiant damping. Our fully quantum mechanical theory provides a universal formula for the decay rate, which reproduces our experimental data without any adjustable parameter. These results firmly establish the many-body nature of CR decoherence in this system, despite the fact that the CR frequency is immune to electron-electron interactions due to Kohn's theorem.
authors.affiliation: Department of Electrical and Computer Engineering, Department of Physics and Astronomy, and Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, USA.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Electrical and Computer Engineering, Department of Physics and Astronomy, and Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, USA.
authors.forename: Takashi
authors.initials: T
authors.lastname: Arikawa
authors.affiliation: Advantest America, Inc., Princeton, New Jersey 08540, USA.
authors.forename: Eiji
authors.initials: E
authors.lastname: Kato
authors.affiliation: Sandia National Laboratories, CINT, Albuquerque, New Mexico 87185, USA.
authors.forename: John L
authors.initials: JL
authors.lastname: Reno
authors.affiliation: Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Pan
authors.affiliation: Department of Physics and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: John D
authors.initials: JD
authors.lastname: Watson
authors.affiliation: Department of Physics, School of Materials Engineering, School of Electrical and Computer Engineering, and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Manfra
authors.affiliation: School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Zudov
authors.affiliation: Institute of Applied Physics, Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia.
authors.forename: Mikhail
authors.initials: M
authors.lastname: Tokman
authors.affiliation: Institute of Applied Physics, Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia.
authors.forename: Maria
authors.initials: M
authors.lastname: Erukhimova
authors.affiliation: Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA.
authors.forename: Alexey
authors.initials: A
authors.lastname: Belyanin
authors.affiliation: Department of Electrical and Computer Engineering, Department of Physics and Astronomy, and Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, USA.
authors.forename: Junichiro
authors.initials: J
authors.lastname: Kono