A team from TU Delft demonstrated a unidirectional superconductor that does not provide resistance in one direction, but completely blocks the current in the other. The discovery, long thought impossible, heralds a 400x jump in processing speed and huge energy savings.
Superconductors can make electronic devices hundreds of times faster and completely eliminate energy loss, but they have only been useful for certain applications, as it has been impossible to prevent them from conducting in all directions without the use of magnetic fields. Building computers without being able to control the direction of the flow? Not possible. So, we’re stuck with semiconductors and Moore’s law is starting to run into their limits.
Hence the greatness of this discovery. Associate Professor Mazhar Ali and a team from TU Delft published new research in the journal Nature which opens the door to superconducting diodes and portends nothing less than a revolutionary change in the speed and energy efficiency of electronics.
Where semiconductors can have a fixed dipole built into it, effectively making it more difficult for electrons to travel in one direction than the other, superconductors have no such built-in potential, so it has only been possible to induce one using a magnetic field. It’s an extremely difficult thing to keep in check at the nanoscale level, so it’s not practical for electronics.
To overcome this limitation, Ali and the team had to introduce a new quantum material under development by a materials physics team at Johns Hopkins University. Like graphene, Nb3fr8 it is a 2D material used in atomically thin slices, but it was theorized that it housed its own electric dipole.
So Ali and his team created what he called “Quantum Material Josephson Junctions” – sandwiches of two superconductors with the quantum material Nb.3fr8 in the middle. “We were only able to peel off a couple of atomic layers of this Nb3fr8 and creating a very, very thin sandwich – only a few atomic layers thick – that was needed to make the Josephson diode and wasn’t possible with normal 3D materials, ”Ali explained in SciTech Daily.
“Many technologies are based on older versions of JJ superconductors,” continued Ali. “For example, MRI technology. Also, quantum computing today is based on Josephson Junctions. Technology that was previously only possible using semiconductors can now potentially be made with superconductors using this building block. This includes faster computers, such as in the computers up to terahertz speed, which is 300 to 400 times faster than the computers we are using now. This will affect all kinds of social and technological applications. If the 20th century was the century of semiconductors, the 21st may become the century of superconductors “.
The researchers built and tested “many devices” using different batches of materials, each time finding a strongly directional Josephson diode result. They tried to reverse the diode and tried to apply various magnetic fields to the junctions to see what effects they could have. The diode showed no resistance in the forward direction, normal resistance in the backward direction, and operated with zero applied magnetic field.
Research to date has been conducted at extremely low temperatures, below 77 Kelvin (-196 ° C, -321 ° F). Therefore, the next challenge is to raise the temperature in an area where electronic devices could realistically be cooled by liquid nitrogen. This says Ali, it should be achievable using “known High Tc superconductors”.
Then there is the production. “The second thing to address is the downsizing of production,” said Ali. “While it’s great to have shown it works in nano devices, we’ve only made a handful of them. The next step will be studying how to scale production to millions of Josephson diodes on a chip.”
Ali says it would make sense to implement this superconducting technology in server farms and supercomputers. “Centralized computing is really the way the world works today,” he said. “All the intensive calculations are done in centralized facilities where localization adds huge advantages in terms of power management, heat management, etc. Existing infrastructure could be adapted without too much cost to work with diode based electronics. Josephson. Possibility, if the challenges discussed in the other question are overcome, that this will revolutionize centralization and supercomputing! “
The research is published in the journal Nature.
Source: SciTech Daily