Nonhomogeneous ultrafast dynamics of anti- and ferromagnetic transient metallic states formation in pulse-excited monoclinic vanadium sesquioxide

Several experiments point to the presence of striped monoclinic (insulating) domains in the antiferromagnetic (AFM) phase of V₂O₃. These domains accommodate the birth of metallic nanodroplets that grow after photoexcitation and transform the state of the system into a metallic phase without lattice reconstruction (insulator-to-metal transition). Using the combination of time-dependent density-functional theory and dynamical mean-field theory we analyze the microscopic details of the initial (0-1ps) growth of the domains in V₂O₃ excited by a laser pulse by tracking the spatially resolved population of the excited V d-orbitals. We find that the preferred expansion of the metallic domains is along the “AFM” vanadium hexagonal planes, in which the photoinduced inter-plane hybridization of the d-states plays an important role. We also analyze details of the growth of the FM metallic domains created by a circularly polarized pulse. In both AFM and FM cases we establish the critical initial domain size and critical pulse fluence that results in a ps domain expansion moving the system into a metastable metallic phase. We compare the results with available recent experimental data and discuss possible application of the findings in terahertz electronic and magnetic switching technologies.