Charge density waves are wave-like modulations of a material’s electron density that display collective amplitude and phase dynamics. The interaction with atomic impurities induces strong spatial heterogeneity of the charge-ordered phase. Direct real-space observation of phase excitation dynamics of such defect-induced charge modulation is absent. Here, by utilizing terahertz pump–probe spectroscopy in a scanning tunnelling microscope, we measure the ultrafast collective dynamics of the charge density wave in the transition metal dichalcogenide 2H-NbSe₂ with atomic spatial resolution. The tip-enhanced electric field of the terahertz pulses excites oscillations of the charge density wave that vary in magnitude and frequency on the scale of individual atomic impurities. Overlapping phase excitations originating from the randomly distributed atomic defects in the surface create this spatially structured response of the charge density wave. This ability to observe collective charge order dynamics with local probes makes it possible to study the dynamics of correlated materials at the intrinsic length scale of their underlying interactions.

电荷密度波是材料电子密度的波状调制，显示集体振幅和相位动态。与原子杂质的相互作用引起电荷有序相的强烈空间异质性。缺乏对这种缺陷引起的电荷调制的相激发动力学的直接实空间观察。在这里，通过在扫描隧道显微镜中利用太赫兹泵浦探针光谱，我们以原子空间分辨率测量了过渡金属二硫属化物 2H-NbSe ₂中电荷密度波的超快集体动力学。太赫兹脉冲的尖端增强电场激发电荷密度波的振荡，其幅度和频率随单个原子杂质的变化而变化。源自表面中随机分布的原子缺陷的重叠相位激发产生了电荷密度波的空间结构化响应。这种用局部探针观察集体电荷序动力学的能力使得研究相关材料在其潜在相互作用的固有长度尺度上的动力学成为可能。