Magnetic-Field-Dependent Multi-Line Cyclotron Resonance in Modulation-Doped GaAs/AlGaAs Quantum Wells

Far-infrared magneto-transmission, magneto-transport and magneto-photoluminescence (PL) measurements have been carried out at low temperatures and high magnetic fields on a high electron density (8.2 × 10^11 cm^ -2) modulation-doped GaAs/AlGaAs multiple-quantum-well sample. Two and three electron cyclotron resonance (CR) lines were clearly resolved in the magnetic field ranges 6.5 to 8.5 T, and 13 to 15 T, respectively. The main features of this multi-line structure and its evolution with magnetic field can be qualitatively understood from a model that accounts for self-consistent band bending (at B = 0), occupancy of Landau levels (LLs) in two subbands, and conduction-band non-parabolicity. Self-consistent calculation in the presence of the magnetic field and electron-electron interactions will be discussed. [2ex] ^1 Supported in part by ONR grant # N000149710858 and NSF grant # DMR-9722625.