Cyclotron resonance in high mobility CdTe/CdMgTe 2D electron system in the integer quantum Hall regime

We performed the cyclotron resonance experiment in high mobility CdTe/CdMgTe 2D electron system (2DES) in quantizing magnetic fields. We observed the sharp single cyclotron resonance and the weak temperature dependence of this resonance. This single cyclotron resonance reminds us about the coupling of two resonances through the electron-electron interaction. The small oscillation of the effective mass was observed at the filling factor nu = 2, 3. This oscillation seems to originate from the polaron effect. Moreover, the effective mass increases abruptly near the LO phonon energy owing to the resonant polaron effect. The impurity cyclotron resonance between 1s-2p(+) and 1s-2p(-) level was also observed. The resonant polaron effect was also conspicuous in impurity cyclotron resonance. (C) 1998 Elsevier Science B.V. All rights reserved.