We study the nonequilibrium dynamics of photoexcited electrons in the narrow-gap Mott insulator ${\mathrm{VO}}_2$. The initial stages of relaxation are treated using a quantum Boltzmann equation methodology, which reveals a rapid ($\sim \text{femtosecond}$ time scale) relaxation to a pseudothermal state characterized by a few parameters that vary slowly in time. The long-time limit is then studied by a Hartree-Fock methodology, which reveals the possibility of nonequilibrium excitation to a new metastable $M_1$ metal phase that is qualitatively consistent with a recent experiment. The general physical picture of photoexcitation driving a correlated electron system to a new state that is not accessible in equilibrium may be applicable in similar materials.

• Received 17 December 2015
• Revised 24 February 2016

DOI:https://doi.org/10.1103/PhysRevB.93.115126