Researchers Built a Superconducting Diode-Like Device with Serious Efficiency Gains

A multi-institutional research team led by scientists at the Massachusetts Institute of Technology (MIT) have designed a simple superconducting diode-like device which, they say, could considerably boost the energy efficiency of computers and other electronic devices in the future.

"Our engineering of a superconducting diode effect that is robust and can operate over a wide temperature range in simple systems can potentially open the door for novel technologies," claims project lead Jagadeesh Moodera, senior research scientist at MIT's Department of Physics. "The effect we found is due [in part] to a ubiquitous property of superconductors that can be realized in a very simple, straightforward manner. It just stares you in the face."

The prototype diode-like device is based on Moodera and colleagues' 2020 discovery of evidence pointing to the existence of Majorana fermions, an exotic particle pair which could prove of use in the construction of quantum computers. Using the material platform originally developed for the Majorana project, the team were able to iterate through a family of superconducting diodes — discovering that the application of a tiny magnetic field could help the devices maintain superconductivity.

Initially, the devices were around 20 percent efficient; as the team progressed in the research, this was increased to 65 percent through a tuning process based on optimizing differences in the shape of the two opposing edges of the device — with Moodera suggesting additional tuning may lead to even higher efficiency gains.

"It is fascinating to see how inconspicuous yet ubiquitous factors can create a significant effect in observing the diode effect," says first author Yasen Hou, who worked with colleagues including two researchers who were still at high school during the project. "What's more exciting is that [this work] provides a straightforward approach with huge potential to further improve the efficiency."

The superconducting diode devices are, the team claims, "easily scalable," and could be produced on silicon wafers — suggesting their use in future computing devices, doubling or more their energy efficiency compared to current semiconductor approaches.

If so, they could be key to taming the growing energy demands of ever-faster computing hardware and ubiquitous electronics — though, at present, the device must be cooled well below room temperature to operate at maximum efficiency.

The team's work is published under open-access terms in the journal Physical Review Letters.