Superradiant decay of cyclotron resonance of two-dimensional electron gases

Qi Zhang; Takashi Arikawa; Eiji Kato; John L Reno; Wei Pan; John D Watson; Michael J Manfra; Michael A Zudov; Mikhail Tokman; Maria Erukhimova; Alexey Belyanin; Junichiro Kono

doi:10.1103/PhysRevLett.113.047601

Superradiant decay of cyclotron resonance of two-dimensional electron gases

Phys Rev Lett. 2014 Jul 25;113(4):047601. doi: 10.1103/PhysRevLett.113.047601. Epub 2014 Jul 21.

Authors

Affiliations

¹ Department of Electrical and Computer Engineering, Department of Physics and Astronomy, and Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, USA.
² Advantest America, Inc., Princeton, New Jersey 08540, USA.
³ Sandia National Laboratories, CINT, Albuquerque, New Mexico 87185, USA.
⁴ Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
⁵ Department of Physics and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA.
⁶ Department of Physics, School of Materials Engineering, School of Electrical and Computer Engineering, and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA.
⁷ School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA.
⁸ Institute of Applied Physics, Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia.
⁹ Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA.

PMID: 25105654
DOI: 10.1103/PhysRevLett.113.047601

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.