Real-time dynamics of energy and angular momentum transfer in ferromagnetic oxide heterostructures

Electrons and spins in crystals interact closely with quantized lattice degree of freedom, determining fundamental electrodynamic behaviors and versatile correlated functionalities. In this talk, we reveal spatio-temporal evolutions of energy and angular momentum carried by electrons and phonons in superlattices composed of ferromagnetic metallic SrRuO₃ and paraelectric SrTiO₃. After the photo-excitation of SrRuO₃, temperatures of electron and spin sub-systems rapidly rise, and then their energy and angular momentum are transferred to the phonon sub-system not only of SrRuO₃ but also of non-magnetic insulating SrTiO₃. By tracing real-time dynamics of energy and angular momentum transfer using pump-probe optical techniques, we discuss the electron-phonon coupling with its magnitude largely enhanced in the two-dimensional limit, the angular momentum transfer from spin to acoustic chiral phonon, and the energy transfer across the superlattices via the coherent phonon transport.