Instrumentation developments in electron energy-loss spectroscopy (EELS) in the scanning transmission electron microscope (STEM) one decade ago paved the way for combining milli-electronvolt energy resolution in spectroscopy with Ångström-sized electron probes, unlocking unexplored realms for solid state physics at the nanometer-scale. The fundamental understanding of the scattering processes involved has made it possible to separate atomically localized signals, providing insights into vibrations at the atomic scale. In this Letter, we outline the experimental, conceptual and theoretical advances in this field and also make comparisons with tip-based optical techniques before discussing future perspectives of this exciting technique. Optimization of dark-field signal collection will play a fundamental role in making this technique more widely applicable to a range of materials problems. The benefits of adding momentum-resolution will also be discussed and a powerful acquisition scheme proposed.
Vibrational and nonlinear optical properties of amine-capped push-pull polyynes by infrared and Raman spectroscopy
用红外光谱和拉曼光谱研究了一系列推拉型多炔化合物的振动性质。强红外和拉曼模式的同时激活，即sp碳链的CC键的集体振动，突出了多炔桥在促进电子给体（D）和受体（A）末端之间的电荷转移方面的有效性，从而表明ad-hoc官能化多炔值得探索作为具有吸引力的一阶光学非线性的有机材料的构建块。这些分子的光学，电子和振动性质进行了研究与密度泛函理论计算的支持下，以及电子和振动的第一超极化率（$β$）。对红外光谱的中低区（800-1600 cm $^{-1}$）进行了详细的分析，寻找了不同sp碳链的特定末端的标记带，从而实现了对sp杂化推拉体系的完整振动表征。
Frequency-dependent electron-phonon coupling and vibrational responses in tight-binding and continuous Dirac models with nuclear velocity correction
Dipartimento di Fisica, Università di Roma La Sapienza（罗马大学物理系）；Dipartimento di Scienze e Metodi dell’Ingegneria, Università di Modena e Reggio Emilia（摩德纳-雷焦艾米利亚大学工程科学与方法系）；CNR-SPIN, Area della Ricerca di Tor Vergata（意大利国家研究委员会自旋电子学研究所托尔维拉塔研究区）
Phase-sensitive tip-enhanced sum frequency generation spectroscopy using temporally asymmetric pulse for detecting weak vibrational signals
Institute for Molecular Science, National Institutes of Natural Sciences（国立自然科学研究所分子科学研究所）；Graduate Institute for Advanced Studies, SOKENDAI（综合研究大学院大学）；Laser-Driven Electron-Acceleration Technology Group, RIKEN SPring-8 Center（RIKEN 春冈中心激光驱动电子加速技术组）；Department of Chemistry, Graduate School of Science, Tohoku University（东北大学理学研究科化学系）
