Nanoscale dynamics across the Mott transition in V2O3


July, 2018


Andrea Ronchi, Pía Homm, Mariela Menghini, Paolo Franceschini, Francesco Maccherozzi, Francesco Banfi, Gabriele Ferrini, Federico Cilento, Fulvio Parmigiani, Sarnjeet S. Dhesi, Michele Fabrizio, Jean-Pierre Locquet, Claudio Giannetti

The phase diagrams of 3d metal oxides provide rich landscapes to explore the non-equilibrium degrees of freedoms during an insulator-to-metal transition (IMT). In these materials, the dynamics of nano-textured insulating and metallic phases is characterized by an unexplored complexity than enables manipulation of phase separation to control the properties of quantum materials on ultrafast timescales. Here, we combine X-ray photoemission electron microscopy and non-equilibrium optical spectroscopy to link the temporal and spatial dynamics of the IMT in the Mott insulator V2O3. We show that metallic droplets, which form at the boundaries of striped insulating domains, act as seeds for the non-equilibrium expansion of the metallic phase triggered by the photo-induced change in the 3d-orbital occupation. We demonstrate that the growth of the metallic phase can be controlled by properly tailoring the light-excitation protocol. Our results unveil the coupled electronic and structural dynamics during an ultrafast IMT and open up the possibility of controlling the ultrafast dynamics of Mott transitions in a way that is inaccessible by thermal means.