Related Experiment Video
Updated: May 10, 2025
11:10
Atomic Layer Deposition of Vanadium Dioxide and a Temperature-dependent Optical Model
Published on: May 23, 2018
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Decoupled few-femtosecond phase transitions in vanadium dioxide.
Christian Brahms1, Lin Zhang2, Xiao Shen3
1School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, UK. c.brahms@hw.ac.uk.
Nature Communications
|April 19, 2025
Summary
The insulator-to-metal phase transition in vanadium dioxide (VO2) is resolved using ultrafast spectroscopy. This study reveals a rapid electronic shift within 10 fs, followed by a slower structural change, clarifying VO2
Area of Science:
- Condensed-matter physics
- Quantum materials science
- Ultrafast spectroscopy
Background:
- The insulator-to-metal phase transition in vanadium dioxide (VO2) remains a fundamental challenge in condensed-matter physics.
- Previous ultrafast spectroscopy methods were limited by temporal resolution and sensitivity to only electronic or structural components.
Purpose of the Study:
- To resolve the electronic and structural dynamics of the VO2 phase transition at their intrinsic timescales.
- To elucidate the interplay between electronic and structural degrees of freedom during photoexcitation.
Main Methods:
- Utilizing ultra-broadband few-femtosecond pump-probe spectroscopy.
- Performing time-resolved measurements to capture ultrafast dynamics.
- Integrating tensor-network simulations and density-functional theory calculations for comparative analysis.
Main Results:
- Photoexcitation induces a bad-metallic phase in VO2 within 10 femtoseconds (fs).
- The complete transition takes approximately 100 fs, featuring electronic oscillations and a transient semi-metallic state with a partial bandgap re-opening.
- Experimental findings align with simulations, indicating a rapid structural transition involving vanadium dimer separation and untwisting on distinct timescales.
Conclusions:
- The study clarifies the coupled electronic and structural nature of the light-induced phase transition in VO2.
- Ultra-broadband few-femtosecond spectroscopy is established as a powerful technique for investigating non-equilibrium dynamics in quantum materials.
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