Observation of retardation effects in the spectrum of two-dimensional plasmons

• Published in: Physical review letters Vol. 90; no. 15; p. 156801
• Main Authors: Kukushkin, I V, Smet, J H, Mikhailov, S A, Kulakovskii, D V, von Klitzing, K, Wegscheider, W
• Format: Journal Article
• Language: English
• Published: United States 18-04-2003
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/physrevlett.90.156801

Retardation effects, theoretically predicted more than 35 years ago, are observed in the spectrum of two-dimensional plasmons in high-electron-mobility GaAs/AlGaAs quantum wells. In zero magnetic field, a strong reduction of the resonant plasma frequency is observed due to the hybridization of the plasma and light modes. In a perpendicular magnetic field B, hybrid cyclotron-plasmon modes appear with a very unusual dependence of the frequency on B field. Experimental results are in excellent agreement with the theory.