Resonance enhanced umklapp Raman processes in GaAs-Ga_1-xAl_xAs superlattices

We report the observation of umklapp Raman scattering of phonons with wavevector of 2nπ d in GaAs-Ga1-xAlxAs superlattices with period d, due to resonance enhancements at transitions from valence band to conduction band minibands. We also observed, for the first time, minizone formation in the spin-orbit split valence band. © 1978.