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A superconducting thermal switch with ultrahigh impedance for interfacing superconductors to semiconductors


A number of current approaches to quantum and neuromorphic computing use superconductors as the basis of their platform or as a measurement component, and will need to operate at cryogenic temperatures. Semiconductor systems are typically proposed as a top-level control in these architectures, with low-temperature passive components and intermediary superconducting electronics acting as the direct interface to the lowest-temperature stages. The architectures, therefore, require a low-power superconductor/semiconductor interface, which is not currently available. Here we report a superconducting switch that is capable of translating low-voltage superconducting inputs directly into semiconductor-compatible (above 1,000 mV) outputs at kelvin-scale temperatures (1 K or 4 K). To illustrate the capabilities in interfacing superconductors and semiconductors, we use it to drive a light-emitting diode in a photonic integrated circuit, generating photons at 1 K from a low-voltage input and detecting them with an on-chip superconducting single-photon detector. We also characterize our device’s timing response (less than 300 ps turn-on, 15 ns turn-off), output impedance (greater than 1 MΩ) and energy requirements (0.18 fJ m−2, 3.24 mV nW−1).

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Fig. 1: High-impedance superconducting switch overview.
Fig. 2: Driving a PIC at 1 K.
Fig. 3: Driving an 8.7 kΩ load using the switch.
Fig. 4: Critical current and inferred temperature versus input power density.

Data availability

The data that support the findings of this study are available within the paper. Additional data are available from the corresponding authors upon reasonable request.


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We thank F. Lecocq for helpful discussions and A. Lita for insight into the fabrication development. Part of this research was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. J.P.A. was supported by a NASA Space Technology Research Fellowship. Support for this work was provided in part by the DARPA Defense Sciences Offices, through the DETECT programme.

Author information




A.N.M., V.B.V., S.M.B. and J.M.S. conceived and designed the experiments. A.N.M. performed the experiments. J.P.A. and A.G.K. analysed and modelled the thermal properties of the device. A.N.M. and V.B.V. fabricated the devices. A.N.M., A.N.T. and S.W.N. analysed the data.

Corresponding authors

Correspondence to A. N. McCaughan or J. M. Shainline.

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Competing interests

The authors declare US patent US10236433B1 (Thermal impedance amplifier).

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Supplementary information

Supplementary Information

Thermal transport modelling—estimation of χabs, and details of crosstalk and lateral heat transport.

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McCaughan, A.N., Verma, V.B., Buckley, S.M. et al. A superconducting thermal switch with ultrahigh impedance for interfacing superconductors to semiconductors. Nat Electron 2, 451–456 (2019).

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