Spin-density waves in a quasi-two-dimensional electron gas

We report an inelastic-light-scattering study of the quasi-two-dimensional electron gas in GaAs/${\mathrm{Al}}_{\mathit{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As quantum-well structures. The spectra of the intersubband spin-density waves are measured as a function of wave vector. Detailed calculations are performed using self-consistent-field theory in which exchange and correlation are included through the local-spin-density approximation. We find good agreement between experiment and theory for both the energy of the spin-density wave at k=0 and the magntidue of the dispersion around k=0.