Calibrated Microwave Reflectance in Low-Temperature Scanning Tunneling Microscopy
| Autor: | Wit, Bareld, Gramse, Georg, Müllegger, Stefan |
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| Rok vydání: | 2023 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | We outline calibrated measurements of the microwave reflection coefficient from the tunnel junction of an ultra-high vacuum low temperature scanning tunneling microscope. The microwave circuit design is described in detail, including an interferometer for enhanced signal-to-noise and a demodulation scheme for lock-in detection. A quantitative, in-situ procedure for impedance calibration based on the numerical 3-error-term model is presented. Our procedure exploits the response of the microwave reflection signal due to the change of the tunneling conductance caused by sub-nm variation of the tunneling distance. Experimental calibration is achieved by a least-squares numerical fit of simultaneously measured conductance and microwave reflection retraction curves at finite conductance. Our method paves the way for nanoscale microscopy and spectroscopy of dielectric surface properties at GHz frequencies and cryogenic temperatures. This opens a promising pathway even for dielectric fingerprinting at the single molecule limit. Comment: The manuscript has been improved in response to reviewer comments. Changes include addition of extra details and verification, updated figure layout to improve clarity, and additional context added to the introduction and conclusion. The conclusions and the underlying data remain the same. 12 pages, 4 figures, submitted to Review of Scientific Instruments |
| Databáze: | arXiv |
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