Ultrafast Dynamics of Coherent Acoustic Phonons in the GaMnAs/GaAs Heterostructure System

Pronounced oscillations were found in the reflectivity curves of ferromagnetic GaMnAs/GaAs heterostructure using pump-probe spectroscopy that are caused by coherent acoustic phonons propagating through the sample. The difference in the oscillations period, damping and amplitude as the phonons travel across the GaMnAs/GaAs interface reflect sin electronic structures and optical properties of these materials. Analysis of the oscillation amplitude indicates that this method provides a novel, non-invasive, and non-destructive way to depth profiling.