Granular Aluminum Superinductors Could Enhance Qubit Performance

(PhysicsWorld) Researchers from Karlsruhe Institute of Technology have built a high impedance inductor, or “superinductor”, from granular aluminium. The superinductor can be directly incorporated into superconducting qubit circuits to produce robust quantum systems.
Creating a superinductor is often laborious. Past approaches used arrays of hundreds of superconducting devices called Josephson junctions to build up a cumulatively large inductance. As a simpler alternative, the research team turned to granular aluminium (grAl), a superconducting material containing a mixture of pure, nanoscale aluminium grains and amorphous aluminum oxide.
The successful use of grAl as a material for qubit circuits could solve many of the problems currently limiting the scaling-up of superconducting quantum processors. Beyond quantum information, grAl superinductors could also be used to make inductance-based photon detectors and high impedance resonators, opening the door for a new generation of superconducting devices.