This superconducting diode could reduce the consumption of quantum computers

Computing consumes huge amounts of energy largely due to heat generation. This is caused by the electrical resistance of the materials used in the circuits. Superconductors are materials which, below a certain temperature, offer no electrical resistance, and could therefore offer a solution to this problem.

In an article published in the journal Physical Review Lettersresearchers from Massachusetts Institute of Technology (MIT) in the United States have just created a diode based on a superconductor. The diode is a component widely used in computers that only lets current flow in one direction. While other researchers have already succeeded in creating superconducting diodes, their efficiency (the difference between the net currents in both directions, divided by the total) was relatively low.

A superconducting diode with record efficiency

This new diode is composed of a layer of niobium or vanadium. To work, it relies on the Meissner effect. By applying a perpendicular magnetic current, this strip of superconductors creates opposing currents at the edges, theoretically identical but going in opposite directions. However, due to structural differences between the two edges, inherent in the manufacturing process, the researchers measured a difference in the current depending on the direction, creating a diode effect with an efficiency of 20%. By adding a ferromagnetic insulator made of europium sulphide, and modifying the shape of one of the edges of the superconductor layer to amplify this effect, they were able to achieve a record efficiency of 65%.

Of course, these are not superconductors that operate at room temperature. Niobium should be kept at a maximum of -264 degrees Celsius, and vanadium at -268°C. However, this diode could be used in quantum computers which already rely on superconductors, in particular for qubits.