Superlattices

We utilized time-resolved pump-probe spectroscopy to generate and detect coherent acoustic phonons (CAPs) in SrRuO₃/SrTiO₃ superlattices with frequencies according to the spatial modulation of the heterostructures. Thanks to the pulse laser deposition techniques, precise manipulation of atomic layers enables the fabrication of high-quality heterostructures and generation of CAPs in THz regime. Dynamics of CAPs from hundreds of GHz to 1 THz were investigated. By introducing a control pulse, coherent control of CAPs was also demonstrated. Since many complex oxides with perovskite structures can be deposited on the SrRuO3/SrTiO3 superlattices, our demonstrated technique can be used to study their coherent acoustic properties in THz regime.