Discovery of the one-way superconductor, thought to be impossible

The discovery of one-way superconductivity without magnetic fields was thought to be impossible until now. The way toward superconducting computing will be made possible by the discovery, which was published in Nature. Electronics can be made hundreds of times faster with superconductors. The 21st century can become the century of the superconductor if the 20th century was the century of semiconductors.

The nature of superconductivity, which was discovered by a Dutch physicist in 1911, has puzzled many scientists during the 20th century. In superconductors, a current goes through a wire without resistance, so it's not possible to block it, or even get the current to flow one way and not the other. It's remarkable that Ali's group was able to make a one-direction superconducting device, which is necessary for computing.

Superconductor is green.

The advantages of applying superconductors to electronics are twofold. If you were to spin a superconducting wire from here to the moon, it would transport the energy without any loss. According to the NWO, up to 10% of the western energy reserves could be saved by using superconductors instead of regular semi-conductors.

It is possible to apply superconducting.

In the 20th century, no one could overcome the barrier of making superconducting electrons go in just one direction, which is a fundamental property needed for computing and other modern electronics. The electrons move in pairs of twos, without any loss of electrical energy, in superconductors. In the 70s, IBM scientists tried out the idea of superconductivity but had to stop because it was impossible to run a computer on it.

Interview with author Mazhar Ali.

When one-way direction works with normal semi-conduction, has one-way superconductivity never worked before?

The net built in potential they can have can be one-way because of a fixed internal electric dipole. The textbook example is the famous pn junction, where we slap together two semiconductors, one with extra electrons and the other with extra holes. An electron flying through the system will feel the separation of charge. This can result in one-way properties because forward vs backwards are no longer the same. The difference in going in the same direction as the dipole and going against it is the same as going up the river.

Since they are related to metals, superconductors never had an analogue of this idea without a magnetic field. Josephson Junctions, which are sandwiches of two superconductors with non-superconducting, classical barrier materials in-between the superconductors, have no symmetry-breaking mechanism that resulted in a difference between forward and backwards.

What first seemed impossible, how did you manage to do it?

It was the result of one of my research directions. The classical barrier material in Josephson Junctions is replaced with a quantum material barrier, where the properties of the quantum materials can be changed in novel ways. The Josephson Diode was an example of this: we used the quantum material Nb 3 Br 8, which is a 2D material like graphene that has been theorized to host a net electric dipole, as our quantum material barrier of choice and placed it between two superconductors.

We were able to peel off a few atomic layers of Nb 3 Br 8 and make a very thin sandwich, which was not possible with normal 3D. The Josephson diode was realized for the first time because of the Nb 3 Br 8 material, which is part of a group of new quantum materials being developed by our collaborators.

What does this discovery mean for applications?

There are many technologies that are based on old versions ofJJ superconductors. Josephson Junctions is the basis of quantum computing today. This building block can be used to make technology which was only possible using semi-conductors. The computers we are using are 300 to 400 times faster than the computers we are using with up to Terahertz speed. This will affect a lot of societal and technological applications. The 21st century can become the century of the superconductor if the 20th century was the century of semi-conductors.

Raising the operating temperature is the first research direction we have to tackle. The operating temperature was limited by using a simple superconductor. We want to work with High Tc Superconductors and see if we can operate Josephson diodes at temperatures above 77 K, since this will allow for liquid nitrogen cooling. Scaling of production is the second thing to tackle. We only made a small number of the devices we proved this works in. The next step is to figure out how to make millions of Josephson diodes on a chip.

How sure are you about your case?

Scientists need to take several steps to maintain scientific rigor. The first thing to do is make sure their results are consistent. We made many devices from scratch, with different batches of materials, and found the same properties on different machines in different countries. The Josephson diode result was coming from our combination of materials and not some spurious result of dirt, geometry, machine or user error.

Smoking gun experiments narrows the possibility for interpretation. To be certain that we had a superconducting diode effect, we tried to switch the diode, but we didn't see any resistance in one direction or normal resistance.

The effect was clearly present at 0 applied field and was killed by an applied field when we measured it. It's a very important point for technological applications that this is a smoking gun for our claim of having a superconducting diode effect at zero applied field. Magnetic fields at the nanometer scale are very difficult to control and limit, so for practical applications, it is generally desired to operate without requiring local magnetic fields.

Is it realistic for ordinary computers to use superconducting?

Yes, it is! It would be smart to implement this for server farms. Centralized computation is how the world works now. Any and all intensive computation is done at centralized facilities where the benefits of localization are huge. If the challenges discussed in the other question are overcome, there is a very real chance that this will change centralized and supercomputing.

More information: Mazhar Ali, The field-free Josephson diode in a van der Waals heterostructure, Nature (2022). DOI: 10.1038/s41586-022-04504-8. www.nature.com/articles/s41586-022-04504-8 Journal information: Nature Citation: Discovery of the one-way superconductor, thought to be impossible (2022, April 27) retrieved 27 April 2022 from https://phys.org/news/2022-04-discovery-one-way-superconductor-thought-impossible.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.