Magnetoplasmon-phonon coupling in a two-dimensional electron gas

Publisher Website
Google Scholar
Abstract
We have studied the coupling of longitudinal-optical (LO) phonons in a polar semiconductor to the collective density oscillations of a two-dimensional electron gas (2DEG) in a strong magnetic field. Both random-phase and time-dependent Hartree-Fock approximations for the electronic contribution to the dielectric function have been considered. The strong field plays an essential role since the magnetoplasmon resonance of the 2DEG occurs near the cyclotron frequency which, for GaAs, becomes comparable to the LO-phonon frequency at available magnetic fields. The coupling of magnetoroton modes [S. M. Girvin, A. H. MacDonald, and P. M. Platzman, Phys. Rev. Lett. 54, 581 (1985)], which are relevant to the fractional quantum Hall effect, to LO phonons is also briefly discussed.