Ultrafast Electron-Lattice Coupling Dynamics in VO2 and V2O3 Thin Films

Abstract

Ultrafast optical pump - optical probe and optical pump - terahertz probe spectroscopy were performed on vanadium dioxide (VO2) and vanadium sesquioxide (V2O3) thin films over a wide temperature range. A comparison of the experimental data from these two different techniques and two different vanadium oxides, in particular a comparison of the electronic oscillations generated by the photoinduced longitudinal acoustic modulation, reveals the strong electron-phonon coupling that exists in the metallic state of both materials. The low energy Drude response of V2O3 appears more susceptible than VO2 to ultrafast strain control. Additionally, our results provide a measurement of the temperature dependence of the sound velocity in both systems, revealing a four- to fivefold increase in VO2 and a three- to fivefold increase in V2O3 across the phase transition. Our data also confirm observations of strong damping and phonon anharmonicity in the metallic phase of VO2, and suggest that a similar phenomenon might be at play in the metallic phase of V2O3. More generally, our simple table-top approach provides relevant and detailed information about dynamical lattice properties of vanadium oxides, opening the way to similar studies in other complex materials.

21 pages, 5 figures, supplemental material included

References in corpus (9)

• Electrodynamics of Correlated Electron Materials
• Evidence for a Structurally-driven Insulator-to-metal Transition in VO2: a View from the Ultrafast Timescale
• Electrodynamics of the vanadium oxides VO2 and V2O3
• Correlated metallic state of vanadium dioxide
• Ultrafast mid-infrared nanoscopy of strained vanadium dioxide nanobeams
• Quasiparticle evolution and pseudogap formation in V2O3: An infrared spectroscopy study
• Correlation-driven insulator-metal transition in near-ideal vanadium dioxide films
• Large epitaxial bi-axial strain induces a Mott-like phase transition in VO2
• Ultrafast evolution and transient phases of the prototype out-of-equilibrium Mott-Hubbard material V2O3

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• Early-stage dynamics of metallic droplets embedded in the nanotextured Mott insulating phase of V${}_2$O${}_3$
• Non-thermal light-assisted resistance collapse in a V${}_2$O${}_3$-based Mott-insulator device
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• Ultrafast insulator-to-metal transition in VO${}_2$ nanostructures assisted by picosecond strain pulses
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• Search for power-efficient wide-range reversible resistance modulation of $V{O}_2$ single crystals