Light scattering from a layered electron gas

The Raman scattering cross section from a two-component layered electron gas (such as in InAs-GaSb, GaAs-${\mathrm{Al}}_{\mathrm{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$As superlattices, etc.) has been calculated. It is found that for a separation between the two components larger than a critical value, the scattered spectra have two resonant peaks in the high-frequency regime. For small separation and small mass ratio, there is a resonant peak due to an ion acoustic mode in the low-frequency regime and to a plasma mode in the high-frequency regime.