Vialla Fabien, Del Fatti Natalia
Institut Lumière Matière UMR 5306, Université Claude Bernard Lyon 1, CNRS, Université de Lyon, F-69622 Villeurbanne, France.
Nanomaterials (Basel). 2020 Dec 17;10(12):2543. doi: 10.3390/nano10122543.
Coherent phonons can be launched in materials upon localized pulsed optical excitation, and be subsequently followed in time-domain, with a sub-picosecond resolution, using a time-delayed pulsed probe. This technique yields characterization of mechanical, optical, and electronic properties at the nanoscale, and is taken advantage of for investigations in material science, physics, chemistry, and biology. Here we review the use of this experimental method applied to the emerging field of homo- and heterostructures of van der Waals materials. Their unique structure corresponding to non-covalently stacked atomically thin layers allows for the study of original structural configurations, down to one-atom-thin films free of interface defect. The generation and relaxation of coherent optical phonons, as well as propagative and resonant breathing acoustic phonons, are comprehensively discussed. This approach opens new avenues for the in situ characterization of these novel materials, the observation and modulation of exotic phenomena, and advances in the field of acoustics microscopy.
在材料中，通过局部脉冲光激发可以产生相干声子，随后使用延时脉冲探针在时域中以亚皮秒分辨率对其进行跟踪。该技术能够在纳米尺度上对材料的力学、光学和电学性质进行表征，并被应用于材料科学、物理学、化学和生物学等领域的研究。在此，我们综述了这种实验方法在范德华材料的同质和异质结构这一新兴领域中的应用。它们独特的结构对应于非共价堆叠的原子级薄层，这使得研究原始结构构型成为可能，甚至可以研究无界面缺陷的单原子薄膜。本文全面讨论了相干光学声子以及传播型和共振呼吸型声学声子的产生和弛豫过程。这种方法为原位表征这些新型材料、观察和调控奇异现象以及声学显微镜领域的发展开辟了新途径。
