Abstract-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, and Junichiro Kono
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.113.047601

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.

DOI: http://dx.doi.org/10.1103/PhysRevLett.113.047601

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• Published 21 July 2014
• Received 5 May 2014

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