Collective Spin-Flip Excitations in the Quantum Hall Regime

In an external magnetic field, the electron inversion layer in GaAs heterojunctions supports collective charge and spin density oscillations, i.e., magnetoplasmons and spin-waves, which, at long wavelengths, can be probed by cyclotron resonance and electron spin resonance experiments. To first order, electron-electron interactions only affect these modes at finite wave vectors and, hence, their effect is not directly probed by such experiments. …