Overview of the vacuum system including cryostat. Please note that most flanges are drawn open for clarity, i.e., without viewports, feedthroughs, or small equipment such as LEED/Auger, etc., in place.
Cryostat with squared and He shields. For better visibility, the front shields are removed, exposing the microscope hanging on springs.
Section view (left; cut along the symmetry plane) and front view (right) of the microscope. For details, see text.
Sketch of the replaceable tip holder with tuning fork and custom tip. Electrical connections from the springs to the tuning fork and tip, respectively, are omitted for clarity. Inset: photo of tip, tuning fork, and STM connection. The wire for collecting the tunneling current has a diameter of .
Example of a resonance curve of a tuning fork with tip attached. The data have been acquired in vacuum at , featuring a resonance frequency of and a factor of .
STM image (raw data) of Cu(111) (, , , scan speed of , image size: ). An electronic surface charge wave, caused by a step edge located just outside the scanned area next to the upper left corner, runs diagonally from upper left to lower right. The arrows on the left indicate the position and orientation of the individual wave fronts. Atomic corrugation is and charge wave corrugation max.
(a) STM image (image size: ) recorded on Cu(111) at with a tunneling current of , an applied bias voltage of , and a scan speed of . Both the atomic surface corrugation as well as the charge modulations originating from several interfering circular charge waves can be observed. The data shown have been slightly Fourier filtered. (b) Section view along the line shown in (a).
[(a) and (b)] Atomically resolved NC-AFM images of HOPG, recorded with constant oscillation amplitudes of and constant scan speeds of using a tuning fork with . The sample has been cleaved in air and subsequently been heated in vacuum to for to remove eventual contamination. The images were recorded at with the PLL bandwidth limited to for (a) and at with PLL bandwidth for (b); image sizes are and , respectively. (c) Section view cut along the line indicated in (b). All data shown are raw data.
Force curve obtained on HOPG; oscillation amplitude was . Note that despite the usage of an etched tip as probe, long-range forces are comparatively small.
Two-dimensional array of 256 force curves recorded along a line of length on HOPG. Contour lines of equal force, plotted every , visualize force variations that are induced by the atomic lattice of the graphite sample. Note that atomic corrugation can be observed up to a height of above the distance of closest approach.
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