We have investigated the far-infrared (FIR) cyclotron resonance (CR) of a two-dimensional electron gas (2DEG) in the presence of a grating coupler to excite plasmons in the 2DEG. We find that only when the coupling between the 2DEG and the metal grating is strong enough to excite 2D plasmons at B=0, the CR shows the anomalous broadening and splitting reported by Schlesinger et al. [Phys. Rev. B 30, 435 (1984)]. Our experiment demonstrates that the anomaly must result from excitation of the 2DEG by spatially periodic components of the FIR field and confirms their original suggestion that it is of electro-electron interaction origin. However, to our knowledge there is still no theoretical explanation for the anomaly.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics