Broadening of cyclotron resonance line of 2-D electron gas in a multiple-quantum-well structure

摘要

The theory of cyclotron resonance (CR) lineshape of a two-dimensional electron gas (2 DEG) due to the electron-phonon interaction in the multiple-quantum-well structures (MQWS) is investigated. The contribution of the deformation potential acoustic and piezoelectric phonon scattering to the broadening of the cyclotron resonance spectra (CRLW) of such a system is calculated for GaAs/AlAs. The piezoelectric phonon scattering contribution to the linewidth is smaller as compared to the deformation potential acoustic phonon scattering but is significantly comparable. The magnetic field dependence of CRLW due to the deformation potential acoustic and piezoelectric phonons is B$+1/2$/ and B$+1/4$/, respectively, and the frequency shift $EQ 0 for both interactions in the elastic scattering approximation. Observed numerical values of the CRLW indicate that at low temperatures acoustic and piezoelectric phonons are dominant scatterers and interact strongly with 2D EG in MQWS where the impurity scattering is suppressed due to the modulation doping. Effect of screening on the scattering of electrons by statically screened longitudinal and transverse piezoelectric phonons in multiple-quantum-wells structures are also reported. Screened transverse phonons are found to play an important role in the scattering process. When the cyclotron orbit lies within the screening radius, CRLW is found to be large compared to the case when the cyclotron orbit lies outside the screening radius. Variation of the CRLW with respect to the magnetic field due to the combined scattering by longitudinal and transverse piezoelectric phonons is studied.