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arXiv · 2210.11908

How cold is the junction of a millikelvin scanning tunnelling microscope?

Taner Esat·Xiaosheng Yang·Farhad Mustafayev·Helmut Soltner·F. Stefan Tautz·Ruslan Temirov
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Abstract

We employ a scanning tunnelling microscope (STM) cooled to millikelvin temperatures by an adiabatic demagnetization refrigerator (ADR) to perform scanning tunnelling spectroscopy (STS) on an atomically clean surface of Al(100) in a superconducting state using normal-metal and superconducting STM tips. Varying the ADR temperatures between 30 mK and 1.2 K, we show that the temperature of the STM junction $T$ is decoupled from the temperature of the surrounding environment $T_{\mathrm{env}}$. Simulating the STS data with the $P(E)$ theory, we determine that $T_{\mathrm{env}} \approx 1.5$ K, while the fitting of the superconducting gap spectrum yields the lowest $T=77$ mK.

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Taner Esat, Xiaosheng Yang, Farhad Mustafayev, Helmut Soltner, F. Stefan Tautz, Ruslan Temirov. 2022-10-21. How cold is the junction of a millikelvin scanning tunnelling microscope?. https://doi.org/10.1038/s42005-023-01201-4

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