Figure: (Upper right) Topographic image (Upper left) STP image (lower) Line profiles70Our STP measurements reveal that the total resistance is dominated by the steps, when the coverage is 1.0 monolayers (ML). This result is well explained by our STM/S measurements, revealing that semiconducting regions are formed in the vicinity of step edges.Poster Award NomineePoster Award NomineeRole of Steps on Transport Measurements Studied by Scanning Tunneling PotentiometryP3-15High-speed Subnanoscale-resolution 2D/3D-AFM Imaging of Calcite Dissolution Process Kazuki Miyata1, A. S. Foster1,2, and T. Fukuma1 1 Nano Life Science Institute (WPI-NanoLSI), Kanazawa University 2 Department of Applied Physics, Aalto University [1] K. Miyata et al., Jpn. J. Appl. Phys., 54, 08LA03 (2015). [2] K. Miyata et al., Nano Lett., 17, 4083-4089 (2017). [3] K. Miyata et al., Nano Lett., 24, 10842-10849 (2024). P3-16Masahiro Haze, Junya Okazaki, Masayuki Hamada, and Yukio HasegawaInstitute for solid state physics, The University of TokyoRecent progress in liquid-environment frequency modulation AFM (FM-AFM) has enabled to visualize atomic-scale 2D height images and 3D force distributions at solid/liquid interfaces. However, its imaging speed (typically ~1 min/frame) has often been too slow to visualize dynamic processes. So far, we have made effort to enhance the measurement bandwidth by improving several key FM-AFM elements, including ultrasmall cantilevers with a megahertz-order resonance frequency in liquid, a low noise wide-band frequency shift detector, a cantilever deflection sensor, a cantilever photothermal excitation system, and Z-tip and XY-sample scanners.[1] With these improvements, we have succeeded in subnanoscale-resolution 2D and 3D imaging of calcite (CaCO3) crystal dissolution processes in water at ~1 s/frame.[2,3] The obtained images revealed the formation of a characteristic transition region (TR) along the step edges. Our simulations suggested that the TR is most likely to be a Ca(OH)2 monolayer formed as an intermediate state in calcite dissolution. Based on this finding, we proposed major improvements in the atomistic calcite dissolution model. Transport property is one of the fundamental information to characterize materials. The transport measurements in nanometer scale are, however, still challenging. By using scanning tunneling potentiometry one can investigate surface conductivity in atomic scales. While most of the works related to STP have been performed at room temperature, to investigate the ground state properties, it is necessary to perform measurements at low temperature. Here, we have demonstrated low temperature STP measurements along with scanning tunneling microscopy/spectroscopy (STM/S) on Pb atomic layer formed on Si(111) to investigate structures, local density of states (LDOS), and transport properties, simultaneously.
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