Raman investigation of plasmon localization in GaAs/AlGaAs superlattices

This work presents a Raman analysis of the influence of disorder in the plasmon localization. The disorder strength control was achieved by growing intentionally disordered GaAs/Al0.3Ga0.7As superlattices. The calculation of the localization extents was made by determining the coherency lengths of the plasmon-LO coupled modes in the frequency range of the AlAs-like optical vibration, that presents a plasmon character. The plasmon damping was obtained from the Raman scattering related to the overdamped plasmon. These calculations allowed us to establish the relationship between the plasmon localization effect and the disorder strength, and to determine the limit of the transition from the delocalization to the strong localization regimes of the plasmon.