Ammerman S E, Jelic V, Wei Y, Breslin V N, Hassan M, Everett N, Lee S, Sun Q, Pignedoli C A, Ruffieux P, Fasel R, Cocker T L
Department of Physics and Astronomy, Michigan State University, East Lansing, MI, 48824, USA.
Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600, Dübendorf, Switzerland.
Nat Commun. 2021 Nov 23;12(1):6794. doi: 10.1038/s41467-021-26656-3.
Atomically precise electronics operating at optical frequencies require tools that can characterize them on their intrinsic length and time scales to guide device design. Lightwave-driven scanning tunnelling microscopy is a promising technique towards this purpose. It achieves simultaneous sub-ångström and sub-picosecond spatio-temporal resolution through ultrafast coherent control by single-cycle field transients that are coupled to the scanning probe tip from free space. Here, we utilize lightwave-driven terahertz scanning tunnelling microscopy and spectroscopy to investigate atomically precise seven-atom-wide armchair graphene nanoribbons on a gold surface at ultralow tip heights, unveiling highly localized wavefunctions that are inaccessible by conventional scanning tunnelling microscopy. Tomographic imaging of their electron densities reveals vertical decays that depend sensitively on wavefunction and lateral position. Lightwave-driven scanning tunnelling spectroscopy on the ångström scale paves the way for ultrafast measurements of wavefunction dynamics in atomically precise nanostructures and future optoelectronic devices based on locally tailored electronic properties.
在光频下运行的原子精确电子器件需要能够在其固有长度和时间尺度上对其进行表征的工具，以指导器件设计。光波驱动扫描隧道显微镜是实现这一目标的一种很有前景的技术。它通过单周期场瞬态的超快相干控制实现了亚埃和亚皮秒级的同时空分辨率，单周期场瞬态从自由空间耦合到扫描探针尖端。在这里，我们利用光波驱动太赫兹扫描隧道显微镜和光谱技术，在超低尖端高度下研究金表面上原子精确的七原子宽扶手椅型石墨烯纳米带，揭示了传统扫描隧道显微镜无法探测到的高度局域化波函数。对其电子密度的断层成像揭示了垂直衰减，这种衰减敏感地依赖于波函数和横向位置。埃尺度上的光波驱动扫描隧道光谱为超快测量原子精确纳米结构和基于局部定制电子特性的未来光电器件中的波函数动力学铺平了道路。
