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arXiv · 2007.10967

Ultrafast light-induced shear strain probed by time-resolved X-ray diffraction: the model multiferroic BiFeO$_3$ as a case study

V. Juvé·R. Gu·S. Gable·T. Maroutian·G. Vaudel·S. Matzen·N. Chigarev·S. Raetz·V. E. Gusev·M. Viret·A. Jarnac·C. Laulhé·A. Maznev·B. Dkhil·P. Ruello
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Abstract

Enabling the light-control of complex systems on ultra-short timescales gives rise to rich physics with promising applications. While crucial, the quantitative determination of both the longitudinal and shear photo-induced strains still remains challenging. Here, by scrutinizing asymmetric Bragg peaks pairs $(\pm h01)$ using picosecond time-resolved X-ray diffraction experiments in BiFeO$_3$, we simultaneously determine the longitudinal and shear strains. The relative amplitude of those strains can be explained only if both thermal and non-thermal processes contribute to the acoustic phonon photogeneration process. Importantly, we also reveal a difference of the dynamical response of the longitudinal strain with respect to the shear one due to an interplay of quasi-longitudinal and quasi-transverse acoustic modes, well reproduced by our model.

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V. Juvé, R. Gu, S. Gable, T. Maroutian, G. Vaudel, S. Matzen, N. Chigarev, S. Raetz, V. E. Gusev, M. Viret, A. Jarnac, C. Laulhé, A. Maznev, B. Dkhil, P. Ruello. 2020-07-21. Ultrafast light-induced shear strain probed by time-resolved X-ray diffraction: the model multiferroic BiFeO$_3$ as a case study. https://doi.org/10.1103/physrevb.102.220303

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