Theory of the Raman Response in Fibonacci Superlattices

A microscopic theory for obtaining the polarized Raman spectrum of Fibonacci chains is developed and applied to GaAs-AlAs heterostructures. The results of the theory, without adjustable parameters, are compared with experimental data, and remarkable agreement is attained. The treatment is performed in real space and, although this system is nonperiodic in a strict sense, it retains many properties usually associated with the translational invariance of crystals. Because of its computational efficiency, this theory is suitable to other finite-size systems.