A Thin-Film Cryotron Suitable For Use as an Ultra-Low-Temperature Switch
Peter J. Lowell, John A. Mates, William B. Doriese, Gene C. Hilton, Kelsey M. Morgan, Daniel S. Swetz, Joel N. Ullom, Daniel R. Schmidt
Low-temperature superconducting circuits have become important in modern science. However, there are presently no high-current-capacity switches with low power dissipation for sub-Kelvin operation. One candidate for a sub-Kelvin switch is the cryotron, a device in which the superconductivity of a wire is suppressed with a magnetic field. Here, we demonstrate a cryotron switch suitable for sub-Kelvin temperatures. In its on state, the maximum device current is about 900 μA. The device is switched to its off state with 1.8 mA and has a leakage current less than 500 nA. The transition between the on and off states of the device is faster than 200 ns; this measurement is limited by the speed of our apparatus. Finally, we present low-temperature applications for our cryotron such as a single-pole, double-throw switch.