Contributors: Tohoku University [Sendai]; Institut des Matériaux de Nantes Jean Rouxel (IMN); Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS)-Nantes université - UFR des Sciences et des Techniques (Nantes univ - UFR ST); Nantes Université - pôle Sciences et technologie; Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Sciences et technologie; Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - Ecole Polytechnique de l'Université de Nantes (Nantes Univ - EPUN); Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ); Institut de Physique de Rennes (IPR); Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS); European Synchrotron Radiation Facility [Grenoble] (ESRF); Lund University; MAX IV Laboratory; Dynamical Control of Materials (DYNACOM); Centre National de la Recherche Scientifique (CNRS); University at Buffalo [SUNY] (SUNY Buffalo); State University of New York (SUNY); Wroclaw University of Science and Technology; Groupe matière condensée et matériaux (GMCM); GREMAN (matériaux, microélectronique, acoustique et nanotechnologies) (GREMAN); Université de Tours (UT)-Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL); Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS); Nagoya University; Japan Science & Technology Agency (JST) - Core Research for Evolutional Science and Technology (CREST) - JPMJCR1901MEXT Q-LEAP - JPMXS0118067426Region Pays de la Loire - Mott-IA projectSwedish Research Council - 2023-05136 and 2018-07152Agence Nationale de la Recherche (ANR) - ANR-22-CPJ2-0053-01Vinnova - 2018-04969Swedish Research Council Formas - 2019-02496; ANR-16-CE30-0018,ELASTICA,Cooperativité Elastique Photo-Induite dans des Matériaux Bistables avec Changement de Volume(2016); ANR-19-CE29-0018,multicross,Trajectoires multiples vers les états excités(2019); ANR-23-CE30-0027,FASTRAIN,Contrôle des transitions de phases ultrarapides dans les matériaux quantiques par la voie athemique des ondes de déformation(2023); ANR-16-IDEX-0007,NExT (I-SITE),NExT (I-SITE)(2016); European Project: 101076203,PhotoDefect
Abstract: Ultrafast photoexcitation can generate internal compressive stress in Mott insulators that lead to strain waves from free surfaces. These photoinduced elastic waves can trigger phase transitions in materials. However, a comprehensive physical picture of the phase transformation dynamics that includes acoustic-scale propagation has not yet been developed. Here we demonstrate that such a strain-wave mechanism drives the ultrafast insulator-to-metal phase transition in granular thin films of the Mott material V2O3. Our time-resolved optical reflectivity and X-ray diffraction measurements reveal that an inverse ferroelastic shear occurs before the insulator-to-metal transition, which propagates in the wake of a compressive strain wave. These dynamics are governed by the domain size and film thickness, respectively. Our results clarify the morphological conditions for the ultrafast phase transition that is favoured in granular thin films and hindered in single crystals. The resulting physical picture sheds light on the ultrafast phase transitions in quantum materials and future devices based on Mott insulators.
This preprint has not undergone peer review or any post-submission improvements or corrections. The Version of Record of this article is published in Nature Physics, and is available online at https://doi.org/10.1038/s41567-024-02628-4
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