Ultrafast physics offers new ways to control materials' macroscopic states through non-thermal pathways. This study reveals that photoinduced elastic waves drive the ultrafast insulator-to-metal transition (IMT) in V₂O₃, a Mott material. Using time-resolved optical reflectivity and X-ray diffraction, the researchers demonstrate the role of strain waves in ultrafast changes with and without symmetry breaking. They observe inverse ferroelastic shear preceding IMT, governed by domain size and film thickness. A fluence threshold for macroscopic IMT is evidenced, along with phase separation at intermediate fluences and complete transformation at high fluences. The study clarifies the morphological conditions favoring ultrafast IMT in granular thin films and hindering it in single crystals.

Tatsuya Amano, Danylo Babich, Ritwika Mandal, Julio Guzman-Brambila, Alix Volte, Elzbieta Trzop, Marina Servol, Ernest Pastor, Maryam Alashoor, Jörgen Larsson, Andrius Jurgilaitis, Van-Thai Pham, David Kroon, John Carl Ekström, Byungnam Ahn, Céline Mariette, Matteo Levantino, Mickael Kozhaev, Julien Tranchant, Benoît Corraze, Laurent Cario, Vinh Ta Phuoc, Rodolphe Sopracase, Mathieu Grau, Hirotake Itoh, Yohei Kawakami, Yuto Nakamura, Hideo Kishida, Hervé Cailleau, Maciej Lorenc, Shinichiro Iwai, Etienne Janod