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Simple modification of the electronics of a STM allows operation in various tracking modes. Profiles of steepest inclination, equal height, equipotential, electrical field lines, etc., can be traced out. The tunnel tip can also be locked to a surface extremity for indefinite time. Some of these possibilities were tested experimentally. [ABSTRACT FROM AUTHOR]

We present an idea to control the progress during focused ion beam milling of cantilevers. Since the monitoring options given by the focused ion beam machine did not satisfy our needs for complete control of the milling process, we decided to measure the current behind the target. A simple current to voltage converter and the electric setup are presented in this Note. [ABSTRACT FROM AUTHOR]

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., (© 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).)

Using a configuration of electrodes connected to charge sensitive amplifiers, the position of a charged particle in free space can be determined in all three dimensions. In our experiment, spheres with a diameter of a millimeter and a charge of about 0.1 pC are traced while they are bouncing at a surface. A spatial resolution of about 0.5 mm combined with a temporal resolution better than 10 µs is achieved. Moreover, the transfer of electric charges when touching a surface can be evaluated.

By cooling a conventional junction field-effect transistor below 150 K, a simple and versatile electrometer with extremely high impedance can be realized. At operating condition, the leakage current to the gate amounts to a few hundredths of an attoampere. The electrometer can be used from DC up to a frequency of 10 kHz. Without reduction of the bandwidth, a sensitivity of a few μV is obtained. Working at low frequencies, currents as low as a few attoamperes can be detected. If the input voltage is out of the operational range, the forward current or the Zener current of the gate junction protects the transistor against destructive charging.