Decoupled few-femtosecond phase transitions in vanadium dioxide
The nature of the insulator-to-metal phase transition in vanadium dioxide (VO<sub>2</sub>) is one of the longest-standing problems in condensed-matter physics. Ultrafast spectroscopy has long promised to determine whether the transition is primarily driven by the electronic or structural degree of freedom, but measurements to date have been stymied by their sensitivity to only one of these components and/or their limited temporal resolution. Here we use ultra-broadband few-femtosecond pump-probe spectroscopy to resolve the electronic and structural phase transitions in VO<sub>2</sub> at their fundamental time scales. Our experiments show that the system transforms into a bad-metallic phase within 10 fs after photoexcitation, but requires another 100 fs to complete the transition, during which we observe electronic oscillations and a partial re-opening of the bandgap, signalling a transient semi-metallic state. Comparisons with tensor-network simulations and density-functional theory calculations show these features result from an unexpectedly fast structural transition, in which the vanadium dimers separate and untwist with two different timescales. Our results resolve the structural and electronic nature of the light-induced phase transition in VO<sub>2</sub> and establish ultra-broadband few-femtosecond spectroscopy as a powerful tool for studying quantum materials out of equilibrium.
Authors
- Johann Osmond (ORCID: https://orcid.org/0000-0001-6522-4695)
- Allan S. Johnson (ORCID: https://orcid.org/0000-0002-0711-708X)
- Kent A. Hallman (ORCID: https://orcid.org/0000-0002-6078-8763)
- Tobias Graß (ORCID: https://orcid.org/0000-0002-8163-9353)
- Xiao Shen (ORCID: https://orcid.org/0000-0003-0200-1931)
- Maria Recasens (ORCID: https://orcid.org/0000-0002-1134-3901)
- Utso Bhattacharya (ORCID: https://orcid.org/0000-0002-1447-443X)
- Maciej Lewenstein (ORCID: https://orcid.org/0000-0002-0210-7800)
- Christian Brahms (ORCID: https://orcid.org/0000-0002-8009-3547)
- John C. Travers (ORCID: https://orcid.org/0000-0003-0350-9104)
- Ravindra W. Chhajlany (ORCID: https://orcid.org/0000-0003-1069-7924)
- Sokrates T. Pantelides (ORCID: https://orcid.org/0000-0002-2963-7545)
- Richard F. Haglund (ORCID: https://orcid.org/0000-0002-2701-1768)
- Lin Zhang (ORCID: https://orcid.org/0000-0002-7071-5955)
Institutions
- Ikerbasque (ES)
- Institució Catalana de Recerca i Estudis Avançats (ES)
- Institute of Photonic Sciences (ES)
- Vanderbilt University (US)
- IMDEA Nanoscience (ES)
- Heriot-Watt University (GB)
- ETH Zurich (CH)
- Donostia International Physics Center (ES)
- Adam Mickiewicz University in Poznań (PL)
- University of Memphis (US)
Publication Details
- Journal
- Nature Communications
- Published
- 2025-04-19
- DOI
- https://doi.org/10.1038/s41467-025-58895-z
- Citations
- 10
- Primary Topic
- Transition Metal Oxide Nanomaterials
- Type
- article
- Field-Weighted Citation Impact
- 6.07
Funders
- National Science Foundation
- U.S. Department of Energy
- Vanderbilt University
- Fundación BBVA
- University of Memphis
- Centres de Recerca de Catalunya
- Institut de Ciències Fotòniques
- Royal Academy of Engineering
- European Commission
- Generalitat de Catalunya
- Eusko Jaurlaritza
- Banco Bilbao Vizcaya Argentaria
- Barcelona Supercomputing Center
- QuantERA
- European Climate, Infrastructure and Environment Executive Agency
- Office of Science
- HORIZON EUROPE Framework Programme
- Engineering and Physical Sciences Research Council
- Agència de Gestió d'Ajuts Universitaris i de Recerca
- European Regional Development Fund
- Agencia Estatal de Investigación
- Basic Energy Sciences