title: Coherent structural dynamics and electronic correlations during an ultrafast insulator-to-metal phase transition in VO2.
abstract: We directly trace the multi-THz conductivity of VO2 during an insulator-metal transition triggered by a 12-fs light pulse. The femtosecond dynamics of lattice and electronic degrees of freedom are spectrally discriminated. A coherent wave packet motion of V-V dimers at 6 THz modulates the lattice polarizability for approximately 1 ps. In contrast, the electronic conductivity settles to a constant value already after one V-V oscillation cycle. Based on our findings, we propose a qualitative model for the nonthermal phase transition.
authors.affiliation: Department of Physics and Center for Applied Photonics, University of Konstanz, D-78457 Konstanz, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Kübler
authors.forename: H
authors.initials: H
authors.lastname: Ehrke
authors.forename: R
authors.initials: R
authors.lastname: Huber
authors.forename: R
authors.initials: R
authors.lastname: Lopez
authors.forename: A
authors.initials: A
authors.lastname: Halabica
authors.forename: R F
authors.initials: RF
authors.lastname: Haglund
authors.forename: A
authors.initials: A
authors.lastname: Leitenstorfer