Ultrafast and persistent photoinduced phase transition at room temperature monitored by streaming powder diffraction
Marius Hervé, Gaël Privault, Elżbieta Trzop, Shintaro Akagi, Yves Watier, Serhane Zerdane, Ievgeniia Chaban, Ricardo Guillermo Torres Ramírez, Céline Mariette, Alix Volte, Marco Cammarata, Matteo Levantino, Hiroko Tokoro, Shin‐ichi Ohkoshi, Éric Collet
Abstract
Abstract Ultrafast photoinduced phase transitions at room temperature, driven by a single laser shot and persisting long after stimuli, represent emerging routes for ultrafast control over materials’ properties. Time-resolved studies provide fundamental mechanistic insight into far-from-equilibrium electronic and structural dynamics. Here we study the photoinduced phase transformation of the Rb 0.94 Mn 0.94 Co 0.06 [Fe(CN) 6 ] 0.98 material, designed to exhibit a 75 K wide thermal hysteresis around room temperature between Mn III Fe II tetragonal and Mn II Fe III cubic phases. We developed a specific powder sample streaming technique to monitor by ultrafast X-ray diffraction the structural and symmetry changes. We show that the photoinduced polarons expand the lattice, while the tetragonal-to-cubic photoinduced phase transition occurs within 100 ps above threshold fluence. These results are rationalized within the framework of the Landau theory of phase transition as an elastically-driven and cooperative process. We foresee broad applications of the streaming powder technique to study non-reversible and ultrafast dynamics.