HiSORセミナー
Visualizing the ultrafast phenomena by pump-probe transmission electron microscopy
日時 2021年10月26日 （火） 16：20～17：30頃
場所 オンライン(Zoom形式)
講師 Takahiro Shimojima
(RIKEN CEMS)
Pump-probe method is a powerful tool for studying the ultrafast phenomena in solids, which can be widely applied to conventional experimental techniques such as photoemission spectroscopy [1] and X-ray diffraction [2]. When a solid is excited by femtosecond pulsed laser, electronic and lattice subsystems are instantaneously decoupled and then exhibit different behaviors for several picoseconds [3]. It is a trend to investigate the complex materials by a combination of the pump-probe measurements which separately detect the electronic and lattice dynamics [4,5]. On the other hand, another direction of pump-probe method is the application to the microscopic probes. Pump-probe ultrafast transmission electron microscope (UTEM) is one of such examples, which improves the time resolution of the TEM from millisecond to picosecond [6]. Since local phenomena in solids generally occur in a short time, visualizing the nanomaterials in motion requires time resolution better than nanosecond. For investigating the dynamics of the functional nanomaterials, we started the construction of UTEM at RIKEN from 2017. In this seminar, I will introduce the details of the UTEM apparatus and our recent data on photo-thermal excitation of magnetic skyrmion motions in nanosecond/nanometer regime [7] and photo-induced coherent acoustic phonons with picosecond/nanometer resolution [8]. I will further discuss the future perspective of UTEM based on our new technique “Five-dimensional scanning TEM”.
[1] T. S. et al., Nature Communications 10, 1946 (2019).
[2] T. S. et al., Advances in X-Ray Chemical Analysis, Japan 49, 163 (2018).
[3] A. Nakamura and T. S. et al., Structural Dynamics 3, 064501 (2016).
[4] S. Gerber et al., Science 357, 71 (2017).
[5] S. Ideta and T.S. et al., Sci. Adv. 4, eaar3867 (2018).
[6] B. Barwick et al., Science 322, 1227 (2008).
[7] T. S. et al., Science Advances 7, eabg1322 (2021).
[8] A. Nakamura and T. S. et al., Nano Letters 20, 4932 (2020).
問合せ先 出田真一郎（放射光科学研究センター）
