Seminars Archive

Mapping the excitation-specific electron, spin and lattice dynamics in spinel Co3O4 thin films with fs-resolution

Abstract
We show a combined femtosecond X-ray emission spectroscopy and broadband transient reflectivity study of spinel Co3O4, a system representing a prototypical case of the intrinsic complexity of transition metal oxides, due to its correlated interaction of electronic, nuclear and spin degrees of freedom. By exciting the ligand-to-metal charge transfer and metal-to-metal charge transfer transitions of the system, we observe excitation-specific coherent and incoherent photoresponses that are mediated by different electron-phonon couplings and involve distinct spin and electronic transient configurations of the Cobalt centres. Our joint investigation rules out a stepwise cascade mechanism in the charge carrier relaxation of the material, showing distinct decay pathways for the two excitation channels and presenting a radically different picture compared to previous time-resolved studies of Co3O4.