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.

5 pages, 4 figures

References in corpus (2)

• Testing the limits of quantum mechanical superpositions
• Terahertz Time-Domain Magnetospectroscopy of a High-Mobility Two-Dimensional Electron Gas

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• Superradiantly limited linewidth in complementary THz metamaterials on Si-membranes
• Terahertz magneto-optical spectroscopy of two-dimensional hole and electron systems
• Cyclotron resonance induced photogalvanic effect in surface states of 200 nm thick strained HgTe films
• Effect of illumination on quantum lifetime in GaAs quantum wells
• Effect of density on microwave-induced resistance oscillations in back-gated GaAs quantum wells