학술논문
Strain Wave Pathway to Semiconductor-to-Metal Transition revealed by time resolved X-ray powder diffraction
Document Type
Working Paper
Author
Mariette, C.; Lorenc, M.; Cailleau, H.; Collet, E.; Guérin, L.; Volte, A.; Trzop, E.; Bertoni, R.; Dong, X.; Lépine, B.; Hernandez, O; Janod, E.; Cario, L.; Phuoc, V. Ta; Ohkoshi, S.; Tokoro, H.; Patthey, L.; Babic, A.; Usov, I.; Ozerov, D.; Sala, L.; Ebner, S.; Böhler, P.; Keller, A; Oggenfuss, A.; Zmofing, T.; Redford, S.; Vetter, S.; Follath, R.; Juranic, P.; Schreiber, A.; Beaud, P.; Esposito, V.; Deng, Y; Ingold, G.; Chergui, M.; Mancini, G. F.; Mankowsky, R.; Svetina, C.; Zerdane, S.; Mozzanica, A.; Wulff, M.; Levantino, M.; Lemke, H.; Cammarata, M.
Source
Subject
Language
Abstract
Thanks to the remarkable developments of ultrafast science, one of today's challenges is to modify material state by controlling with a light pulse the coherent motions that connect two different phases. Here we show how strain waves, launched by electronic and structural precursor phenomena, determine a macroscopic transformation pathway for the semiconducting-to-metal transition with large volume change in bistable Ti$_3$O$_5$ nanocrystals. Femtosecond powder X-ray diffraction allowed us to quantify the structural deformations associated with the photoinduced phase transition on relevant time scales. We monitored the early intra-cell distortions around absorbing metal dimers, but also long range crystalline deformations dynamically governed by acoustic waves launched at the laser-exposed Ti$_3$O$_5$ surface. We rationalize these observations with a simplified elastic model, demonstrating that a macroscopic transformation occurs concomitantly with the propagating acoustic wavefront on the picosecond timescale, several decades earlier than the subsequent thermal processes governed by heat diffusion.
Comment: 30 pages (including supplementary text), 5 main figures, 9 supplementary figures; corrected author list
Comment: 30 pages (including supplementary text), 5 main figures, 9 supplementary figures; corrected author list