Ultrafast control of matter by a strong electromagnetic field on the atomic scale is essential for future investigations and manipulations of ionization dynamics and excitation in solids. Coupling picosecond duration terahertz pulses to metallic nanostructures allows the generation of extremely localized and intense electric fields. Here, using single-cycle terahertz pulses, we demonstrate control over field ion emission from metallic nanotips. The terahertz near field is shown to induce an athermal ultrafast evaporation of surface atoms as ions on the subpicosecond time scale, with the tip acting as a field amplifier. The ultrafast terahertz-ion interaction offers unprecedented control over ultrashort free-ion pulses for imaging, analyzing, and manipulating matter at atomic scales. Here, we demonstrate terahertz atom probe microscopy as a new platform for microscopy with atomic spatial resolution and ultimate chemical resolution.
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http://dx.doi.org/10.1126/sciadv.abd7259 | DOI Listing |
J Colloid Interface Sci
December 2024
State Key Laboratory of Photocatalysis On Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou 350108, PR China. Electronic address:
The development of durable and highly efficient visible-light-driven photocatalysts is essential for the photocatalytic ozonation process towards degrading organic pollutants. This study presents CN-MA, a novel photocatalyst synthesized by grafting carbon nitride (CN) with single-atom Mn and 2-hydroxy-4,6-dimethylpyrimidine (HDMP) via one-step thermal polymerization. Experimental characterization and theoretical calculation results reveal that incorporating single-atom Mn and HDMP into CN alters the charge density distribution on the heptazine rings.
View Article and Find Full Text PDFChemistry
December 2024
Lanzhou University, College of Chemistry and Chemical Engineering, Lanzhou Tianshui south street 222, 730000, Lanzhou, CHINA.
Dual single-atom catalysts have attracted considerable research interest due to their higher metal atom loading and more flexible active sites compared to single-atom catalysts (SACs). We pioneered the one-step synthesis of sheets copper-cobalt graphitic carbon nitride dual single-atom (S-Cu/Co-g-C3N4) using folding fan-shaped aluminum foil as a template, and used them as catalysts in the epoxidation of styrene respectively. Through XAFS(X-ray Absorption Fine Structure) and other characterizations, it is found that Cu and Co single atoms are stabilized separately on g-C3N4 via coordination with nitrogen (N), hindered the ordered growth of sheets, and formed more pore structures, which not only increased more catalytically active sites, but also effectively prevented the flakes re-aggregate during the catalytic process.
View Article and Find Full Text PDFCommun Mater
December 2024
Department of Materials Science and Engineering, University of Washington, Seattle, WA USA.
Dental enamel is subjected to a lifetime of de- and re-mineralization cycles in the oral environment, the cumulative effects of which cause embrittlement with age. However, the understanding of atomic scale mechanisms of dental enamel aging is still at its infancy, particularly regarding where compositional differences occur in the hydroxyapatite nanocrystals and what underlying mechanisms might be responsible. Here, we use atom probe tomography to compare enamel from a young (22 years old) and a senior (56 years old) adult donor tooth.
View Article and Find Full Text PDFACS Photonics
December 2024
School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, U.K.
Tightly confined plasmons in metal nanogaps are highly sensitive to surface inhomogeneities and defects due to the nanoscale optical confinement, but tracking and monitoring their location is hard. Here, we probe a 1-D extended nanocavity using a plasmonic silver nanowire (AgNW) on mirror geometry. Morphological changes inside the nanocavity are induced locally using optical excitation and probed locally through simultaneous measurements of surface enhanced Raman scattering (SERS) and dark-field spectroscopy.
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December 2024
Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, USA; Department of Biochemistry, University of Utah, Salt Lake City, UT, USA; Department of Molecular Pharmaceutics, University of Utah, Salt Lake City, UT, USA. Electronic address:
As major adhesion receptors, integrins transmit biochemical and mechanical signals across the plasma membrane. These functions are regulated by transitions between bent and extended conformations and modulated by force. To understand how force on integrins mediates cellular mechanosensing, we compared two highly homologous integrins, αβ and αβ.
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