The ultrafast elastic light scattering technique is applied to reveal the strong nonlinearity of ${\mathrm{V}}_3{\mathrm{O}}_5$ associated with a photoinduced insulator-metal phase transition. Observation of time-domain relaxation dynamics suggests several stages of structural transition. We discuss the nonequilibrium processes in ${\mathrm{V}}_3{\mathrm{O}}_5$ in terms of photoinduced melting of a polaronic Wigner crystal, coalescence of V-O octahedra, and photogeneration of acoustical phonons in the low-$T$ and high-$T$ phases of ${\mathrm{V}}_3{\mathrm{O}}_5$. A molecular dynamics computation supports experimentally observed stages of ${\mathrm{V}}_3{\mathrm{O}}_5$ relaxation dynamics.

• Received 23 March 2017

DOI:https://doi.org/10.1103/PhysRevLett.119.057602