Regensburg 2025 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 11: Superconductivity: Poster
TT 11.25: Poster
Montag, 17. März 2025, 15:00–18:00, P4
Simulations of heating effects in dual Shapiro step circuits — •Matthias Meiring, Fabian Kaap, Sergey Lotkhov, and Lukas Grünhaupt — Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig
So-called dual Shapiro steps are quantised current steps separated by 2ef, with e the elementary charge and f the rf drive frequency. They have recently gained renewed interest due to successful experimental demonstrations [1,2,3]. These dual Shapiro steps could bear the potential for a novel quantum current standard. Our measurements of dual Shapiro steps in an Al/AlOx/Al dc-SQUID connected to a circuit made of high-kinetic-inductance granular aluminium and high-ohmic oxidised titanium revealed an electron temperature, which is substantially higher compared to the case without rf drive. We evaluate thermal heating phenomena in the measured chip layout and present adapted circuit designs, which should reduce heating effects and enhance the step size. Achieving this will lead to more prominent dual Shapiro steps and could thus pave the way to a new quantum current standard based on superconducting circuits.
[1] R.S.Shaikhaidarov et al., Nature 608 (2022).
[2] N. Crescini et al., Nat. Phys. 19 (2023).
[3] F. Kaap et al., Nat. Commun. 15 (2024).
Keywords: Josephson effect; Shapiro steps; Superconductivity; Current standard