SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, UK.
Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, 75005 Paris, France.
Science. 2020 Mar 6;367(6482):1124-1127. doi: 10.1126/science.aba1136.
Single-atom impurities and other atomic-scale defects can notably alter the local vibrational responses of solids and, ultimately, their macroscopic properties. Using high-resolution electron energy-loss spectroscopy in the electron microscope, we show that a single substitutional silicon impurity in graphene induces a characteristic, localized modification of the vibrational response. Extensive ab initio calculations reveal that the measured spectroscopic signature arises from defect-induced pseudo-localized phonon modes-that is, resonant states resulting from the hybridization of the defect modes and the bulk continuum-with energies that can be directly matched to the experiments. This finding realizes the promise of vibrational spectroscopy in the electron microscope with single-atom sensitivity and has broad implications across the fields of physics, chemistry, and materials science.
单原子杂质和其他原子尺度的缺陷可以显著改变固体的局部振动响应，并最终改变其宏观性质。我们使用电子显微镜中的高分辨率电子能量损失光谱，表明在石墨烯中单个替代硅杂质会引起振动响应的特征局部修饰。广泛的从头算计算表明，所测量的光谱特征源于缺陷诱导的赝局域声子模式，即由于缺陷模式与体连续体的杂化而产生的共振态，其能量可以直接与实验匹配。这一发现实现了电子显微镜中具有单原子灵敏度的振动光谱的承诺，并在物理、化学和材料科学领域具有广泛的意义。
