Cyclotron–Phonon Resonance in Quantum Well Structures

The coefficient of electromagnetic radiation absorption by free charge carriers in a dimensionally quantized semiconductor film in a quantizing magnetic field directed perpendicularly to the film's borders has been theoretically calculated. For the first time ever the reconfiguration of the polarized optical vibrations spectrum has been taken into account. It has been demonstrated that both for bulk and interface phonons the absorption has a resonance character. Particularly, electron scattering on bulk optical phonons results in resonance absorption at ω = |nω _c ± ω ₀| frequencies, where ω _c is cyclotron frequency, n is integer number, and absorption lines present delta-shaped peaks. Scattering on interface optical phonons is also of a resonance character, however, due to dispersion of interface phonons frequency Ω _s = Ω _s (η, d), d is the depth of a quantum well, the form of peaks qualitatively differs from the form of bulk peaks: (a) the arcs have the final half-width defined by Ω _s (η, d) dispersion; (b) the peak's maximums are displaced against one another, which makes it possible to identify them in the experiment.