Coupling of spin waves with charge- and spin-density excitations in spin-polarized quantum wells

The coupling of spin waves with charge- and spin-density waves is shown to be induced by a spin-dependent interaction in a quantum well, which is spin polarized by a dc magnetic field at an angle $\theta$ to the symmetry axis. The mixing of the plasmonic and magnonic modes, which occurs for both intra- and intersubband transitions, depends on the coupling constant of the spin-spin interaction, the tilt angle $\theta ,$ and the initial spin polarization $\zeta .$