Interface effects on magnetopolarons in ${\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}/\mathrm{A}\mathrm{l}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$ quantum wells at high magnetic fields

Effects due to interface optical-phonon modes on the cyclotron resonance in high magnetic field are investigated for ${\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}/\mathrm{A}\mathrm{l}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$ quantum wells with the inclusion of band nonparabolicity. The polaron cyclotron resonant frequencies are obtained from the magneto-optical absorption spectrum which exhibits magnetopolaron resonances near the GaAs and AlAs-like phonon frequencies. Our theoretical results are in good agreement with recent cyclotron resonance experiments. Furthermore, we present calculations of interface-phonon-assisted harmonics at high frequency whose positions are determined by the resonant phonon frequencies.