Picosecond anisotropic phase separation governing photoinduced phase stability in submicron Ti₃O₅ crystals

Recently developed ceramic material Ti₃O₅ exhibits fascinating application properties, from ultrafast switching between metallic and insulating phases to light-to-heat conversion and storage. While the states conferring such properties are not spatially homogeneous, the origin of phase separation and the link between the phase coexistence and dynamics, key for stability of such states, is still little known. In this work, we use time-resolved X-ray diffraction and numerical simulations to establish rules by which the dynamics of heat-driven transition in laser excited Ti₃O₅ crystallites occur in space and time. The studies are conducted on submicron Ti₃O₅ crystallites and span a broad timescale allowing separation of phase change regimes. Our results reveal the influence of nanoscopic morphology on the mechanism of macroscopic transformation triggered by laser excitation.