Recent Advances in Ultrafast Structural Techniques

Sciaini, Germán

doi:10.3390/app9071427

Cited by 15 publications

(7 citation statements)

References 284 publications

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“…As a consequence, an increasingly broad range of phenomena in the solid-state can be directly observed in single crystal, polycrystalline, monolayer and heterostructured specimens. For a survey of the landmark works in the field, we refer the readers to previous reviews (Sciaini (2019); Sciaini and Miller (2011);Zewail (2006)).…”

Section: Examples From Literaturementioning

confidence: 99%

Ultrafast Electron Diffraction: Visualizing Dynamic States of Matter

Filippetto,

Musumeci,

et al. 2022

Preprint

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Since the discovery of electron-wave duality, electron scattering instrumentation has developed into a powerful array of techniques for revealing the atomic structure of matter. Beyond detecting local lattice variations in equilibrium structures with the highest possible spatial resolution, recent research efforts have been directed towards the long sought-after dream of visualizing the dynamic evolution of matter in real-time. The atomic behavior at ultrafast timescales carries critical information on phase transition and chemical reaction dynamics, the coupling of electronic and nuclear degrees of freedom in materials and molecules, the correlation between structure, function and previously hidden metastable or nonequilibrium states of matter. Ultrafast electron pulses play an essential role in this scientific endeavor, and their generation has been facilitated by rapid technical advances in both ultrafast laser and particle accelerator technologies. This review presents a summary of the remarkable developments in this field over the last few decades. The physics and technology of ultrafast electron beams is presented with an emphasis on the figures of merit most relevant for ultrafast electron diffraction (UED) experiments. We discuss recent developments in the generation, manipulation and characterization of ultrashort electron beams aimed at improving the combined spatio-temporal resolution of these measurements. The fundamentals of electron scattering from atomic matter and the theoretical frameworks for retrieving dynamic structural information from solid-state and gas-phase samples is described. Essential experimental techniques and several landmark works that have applied these approaches are also highlighted to demonstrate the widening applicability of these methods. Ultrafast electron probes with ever improving capabilities, combined with other complementary photonbased or spectroscopic approaches, hold tremendous potential for revolutionizing our ability to observe and understand energy and matter at atomic scales.

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Section: Examples From Literaturementioning

confidence: 99%

Ultrafast Electron Diffraction: Visualizing Dynamic States of Matter

Filippetto,

Musumeci,

et al. 2022

Preprint

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“…The latter has been exploited as a parameter to follow the aforementioned first-order thermal phase change 11,15,16 as well as possible PIPTs. 17−20 Furthermore, the use of femtosecond electron diffraction (FED) 21,22 has recently revealed that photoexcitation of the T d -MoTe 2 state, in the visible and mid-infrared spectral regions, leads to an interlayer shear displacement of only few picometers (pm), 19 that is, a much smaller magnitude than the actual displacement necessary for the complete transition to the 1T′ phase ≈ 19 pm. 19 This finding is also consistent with the partial interlayer shear motion of ≈ 8 pm observed via relativistic FED in the analogous T d -WTe 2 compound following intense terahertz (THz) excitation.…”

Section: ■ Introductionmentioning

confidence: 99%

Persistent Photogenerated State Attained by Femtosecond Laser Irradiation of Thin T_d-MoTe₂

et al. 2022

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Laser excitation has emerged as a means to expose hidden states of matter and promote phase transitions on demand. Such laser-induced transformations are often rendered possible owing to the delivery of spatially and/or temporally manipulated light, carrying energy quanta well above the thermal background. Here, we report time-resolved broadband femtosecond (fs) transient absorption measurements on thin flakes of the Weyl semimetal candidate T d-MoTe2 subjected to various levels and schemes of fs-photoexcitation. Our results reveal that impulsive fs-laser irradiation alters the interlayer behavior of the low temperature T d phase as evidenced by the persistent disappearance of its characteristic coherent 1A1 ≈ 13 cm–1 shear phonon mode. We found that this structural transformation is likely related to lattice strain formation, withstands thermal cycling, and can be reverted to the 1T′ phase by fs-laser treatment at room temperature. Since interlayer shear strain was encountered to lead to a topologically distinct phase in an analogous compound, our work opens the door to the reversible optical control of electronic properties in this class of materials.

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“…Рентгеновское излучение в настоящее время находит все более широкое применение в физике твердого тела, кристаллографии, микроскопии, спектроскопии, визуализации и в других аналитических задачах [1][2][3]. Существенно, что в работах, ориентированных на исследования конденсированных сред, находящихся в неравновесных состояниях, часто рассматривают лишь относительно низкочастотные атомные смещения.…”

Section: Introductionunclassified

“…Отметим, что для реализации атомного пространственного разрешения, как правило, требуется относительно жесткое рентгеновское излуче-ние (с энергией рентгеновских фотонов более 6 keV,) свободно распространяющееся в воздухе. Для решения задач, ориентированных на нестационарный структурный анализ и на получение дифракционной картины за малое (единицы пикосекунд) время, необходим лазерный микроплазменный источник с высоким выходом характеристических рентгеновских фотонов -около 10 8 ph/s [1,3]. Обычно, лазерно-плазменные источники рентгеновского излучения получаются при фокусировке излучения мощных импульсных лазеров на мишень, расположенную в вакуумной камере [3].…”

Section: Introductionunclassified