Intersubband magnetoplasmon as a detector of the spin polarization in two-dimensional electron systems

The magnetic field dynamics of intersubband collective excitations in two-dimensional electron systems based on Mg$_{x}$Zn$_{1-x}$O/ZnO heterostructures is studied by the Raman scattering method. It is found that, upon the change in the spin polarization under conditions of the transition from the filling factor $\nu=2$ to $\nu=1$, the energy of the intersubband magnetoplasmon changes considerably. The performed theoretical analysis shows that this effect is attributed to the concomitant change in the exchange interaction in the excitation energy.