ANR PRC SYNCHROSTRAIN

Dates :

Du 01 Octobre 2026 au 30 Septembre 2030

Laboratoire Coordinateur du projet : Institut de Physique de Rennes (IPR, UMR 6251)

Coordinateur du projet : Marina SERVOL, Maîtresse de conférences

Coordinateur IMN du projet : Benoît CORRAZE, équipe PMN

Laboratoires partenaires :

• IPR (UMR 6251 CNRS/ Univ. Rennes 1)
• GREMAN (UMR 7347 CNRS/ Université de Tours)
• IMN (UMR 6502 CNRS/ Nantes Université)

Personnel IMN impliqué :
Benoît CORRAZE (MC Univ), Etienne JANOD (DR CNRS), Laurent CARIO (DR CNRS)

Phase transitions can be induced either at equilibrium by gradual change in pressure or temperature, or by impulsive control parameters such as ultra-short optical or THz pulses or also microsecond pulses such as electrical ones. In these fast or ultrafast dynamic situations, the direct effects of the control parameter are not the only phenomena involved in the transition. Whether it is the electronic excitation for the optical pulse, the ultrafast local electric field of the THz pulse, or the macroscopic electric field of an electrical pulse, the impulsive nature of the excitation generates local deformation of the crystal lattice and induces an elastic wave that displaces the atoms. By this way, the interactions between atomic potentials are modulated and metastable states with different, and possibly novel, physical properties can arise. This is able to generate or amplify the phase transition. The involvement of these elastic effects is therefore universal, and studying them has led to a better understanding of out-of-equilibrium phase transitions, which are far less well understood than those at equilibrium. Thus, in recent years, several studies in the photoinduced phase transition (PIPT) domain have revealed the nature of the strain wave and its action on the matter. They have begun to reveal a variety of behaviors. In the Mott insulator Ca2RuO4, the final electronic transformation in the PIPT from the insulator to the metallic state occurs after the isosymetric lattice rearrangement. In other compounds, like in the trititanium pentoxide Ti3O5 the strain and the phase transition fronts propagate simultaneously. In the case of a granular film of chromium doped vanadium sesquioxide, V2O3: Cr, another Mott insulator compound, the insulating to metallic phase transition (IMT) under 160 K implies a breaking symmetry. The corresponding PIPT involves a shear wave concomitant to the transition at the grain scale and then a longitudinal wave propagating the transition at the whole film scale. Until now, no study has concentrated about driving an ultrafast transition only through the propagation of a moderate strain: either the transition is initiated by photo-excitation, either the strain is in the high deformation regime of a shock and the transition is non-volatile. In this project we aim to implement a novel approach to drive a volatile phase transition specifically by a pure well-controlled strain wave, regardless of the influence of the initial pulse, and so from the initial locally induced precursors to the macroscopic transition that it may create.