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We report on a lightwave-driven scanning tunneling microscope based on a home-built microscope and a compact, commercial, and cost-effective terahertz-generation unit with a repetition rate of 100 MHz. The measurements are performed in an ultrahigh vacuum at temperatures between 8.5 and 300 K. The cross-correlation of the pump and probe pulses indicates a temporal resolution on the order of a picosecond. In terms of spatial resolution, CO molecules, step edges, and atomically resolved terraces are readily observed in terahertz images, with sometimes better contrast than in the topographic and (DC) current channels. The utilization of a compact, turn-key terahertz-generation system requires only limited experience with optics and terahertz generation, which may facilitate the deployment of the technique to further research groups.
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http://dx.doi.org/10.1063/5.0165719 | DOI Listing |
Rev Sci Instrum
February 2024
Faculty of Physics, University of Duisburg-Essen, 47057 Duisburg, Germany.
We report on a lightwave-driven scanning tunneling microscope based on a home-built microscope and a compact, commercial, and cost-effective terahertz-generation unit with a repetition rate of 100 MHz. The measurements are performed in an ultrahigh vacuum at temperatures between 8.5 and 300 K.
View Article and Find Full Text PDFACS Photonics
November 2023
nanotech@surfaces Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland.
The fundamental understanding of quantum dynamics in advanced materials requires precise characterization at the limit of spatiotemporal resolution. Ultrafast scanning tunneling microscopy is a powerful tool combining the benefits of picosecond time resolution provided by single-cycle terahertz (THz) pulses and atomic spatial resolution of a scanning tunneling microscope (STM). For the selective excitation of localized electronic states, the transient field profile must be tailored to the energetic structure of the system.
View Article and Find Full Text PDFMicromachines (Basel)
February 2023
University of Science and Technology of China, Hefei 230026, China.
Nat Commun
November 2021
Department of Physics and Astronomy, Michigan State University, East Lansing, MI, 48824, USA.
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.
View Article and Find Full Text PDFNature
September 2020
Department of Physics, University of Regensburg, Regensburg, Germany.
Scanning probe techniques can leverage atomically precise forces to sculpt matter at surfaces, atom by atom. These forces have been applied quasi-statically to create surface structures and influence chemical processes, but exploiting local dynamics to realize coherent control on the atomic scale remains an intriguing prospect. Chemical reactions, conformational changes and desorption have been followed on ultrafast timescales, but directly exerting femtosecond forces on individual atoms to selectively induce molecular motion has yet to be realized.
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