%0 Electronic Article
%A Esat, Taner
%A Yang, Xiaosheng
%A Mustafayev, Farhad
%A Soltner, Helmut
%A Tautz, Frank Stefan
%A Temirov, Ruslan
%T How cold is the junction of a millikelvin scanning tunnelling microscope?
%I arXiv
%M FZJ-2025-02311
%D 2022
%X 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.
%K Mesoscale and Nanoscale Physics (cond-mat.mes-hall) (Other)
%K FOS: Physical sciences (Other)
%F PUB:(DE-HGF)25
%9 Preprint
%R 10.48550/ARXIV.2210.11908
%U https://juser.fz-juelich.de/record/1041554