Abstract：
Thermal vibration properties of nanometer-scale objects are critical for their application in devices such as nanomechanical resonators. An imaging method has been developed which allows the direct visualization of higher-order thermal vibration modes at room temperature, which have so far been inaccessible to observation due to their subangstrom amplitudes and the much stronger overlapped first mode. This technique, combining aberration-corrected scanning transmission electron microscopy with broad-band signal acquisition in the time domain, can display the amplitude distribution of several thermal vibration modes simultaneously by selecting specific frequency windows. This is showcased by mapping the first six thermal vibration modes of a singly clamped nanowire and comparing them to natural vibration mode profiles obtained by finite element calculations. This implementation furthers our understanding of the collective Brownian motion of nanostructures and extends the analysis capabilities of electron microscopy.
摘要：
纳米级物体的热振动特性对于它们在诸如纳米机械谐振器之类的设备中的应用至关重要。已开发出一种成像方法，该方法可以在室温下直接可视化高阶热振动模式，到目前为止，由于它们的亚波段振幅和更强的重叠第一模式，它们无法观测到。这项技术,将像差校正扫描透射电子显微镜与宽带时域信号采集相结合，可以通过选择特定的频率窗口同时显示几种热振动模式的振幅分布。通过映射单夹持纳米线的前六个热振动模式并将它们与通过有限元计算获得的自然振动模式轮廓进行比较来展示这一点。这种实现方式进一步加深了我们对纳米结构的集体布朗运动的理解，并扩展了电子显微镜的分析能力。
