Insight view of a dilution refrigerator in which measurements at very low temperature (around -273 degree centigrade) take place. Image: University of Konstanz

Bridging superconductor and semiconductor technology

International research network SuperGate spearheaded by the University of Konstanz creates an interface between superconductors and semiconductors for future supercomputers – funded through an FET Open Grant of the European Union

The next generation of supercomputers – including quantum computers – is at a crucial point: Tomorrow's high-performance computers are at their physical limit in terms of miniaturization of their components; at the same time, they must be more energy-efficient and increase in performance. In this context, the international research network SuperGate coordinated by the University of Konstanz is creating a new basis: The researchers are developing a bridging technology that combines superconductor technology with semiconductor technology, using an approach that was considered physically impossible until just a few years ago. “We are opening a completely new scientific field here”, says Prof. Angelo Di Bernardo, a physics professor in Konstanz, who jointly with Prof. Wolfgang Belzig and Prof. Elke Scheer forms the Konstanz team of the international research network. The research project is funded with around 3 million euros through an FET Open Grant (FET: Future and Emerging Technologies) of the European Union.

“Superconductor technology and semiconductor technology rely on completely different concepts”, explains Elke Scheer: Semiconductors are controlled by voltage and operate at room temperature. Superconductors, on the other hand, are based on current and operate at temperatures of around -270 degree centigrade, near absolute zero. It is of great interest in high-performance computer development to combine the more powerful and more energy-efficient superconductor technology with existing semiconductor technology. Until a few years ago, however, both systems were considered incompatible.

A path-breaking discovery
In 2018 researchers made a path-breaking discovery: Physicists at the Istituto Nanoscienze CNR at NEST – Scuola Normale Superiore in Pisa (Italy) demonstrated that it was also possible to use voltage to control the current in superconductors. “The basic proof was provided, but how exactly and why this works is still not entirely clear”, says Angelo Di Bernardo. “Now we need to detect the underlying physical mechanism. If we understand that mechanism and the principles behind it, we can control it and use it for technical applications.”

This fundamental discovery paves the way for hybrid computing platforms that combine superconductor with semiconductor technology. “Our aim is to design high-performance superconducting circuits that can be operated as if they were based on semiconductor technologies – and thus combine the advantages of both systems”, underlines Elke Scheer.

Four steps to achieve the goal
The international project cooperation includes four steps: “Firstly, we will shed light onto the physical mechanism that makes it possible to control the state of a superconducting material via the application of a voltage”, specifies Angelo Di Bernardo. “Secondly, we will research which are the best materials for technical applications. The third step will be to implement our concepts in a prototype device, and our fourth and final goal is to integrate this new superconductor technology in an electric circuit which interacts with conventional semiconductor technology.”

FET Open Grant
The collaborative research project, which is coordinated by Elke Scheer and which is jointly performed with Angelo Di Bernardo and Wolfgang Belzig, is funded through an FET Open Grant. With this highly competitive funding programme, the EU supports the early stages of new ideas towards the development of radically new future technologies. Alongside the University of Konstanz and the CNR laboratories at Pisa and Salerno, also the Budapest University of Technology and Economics, the Delft University of Technology and the Chalmers University of Technology at Gothenburg as well as partners from industry (SeeQC) in Italy are involved in the project.

Key facts:

  • The international research network “Gate Tuneable Superconducting Quantum Electronics” (SuperGate) is funded through an FET Open Grant of the European Union.
  • Funding sum: around 3 million euros
  • Funding period: March 2021 to August 2024
  • Project coordination: Professor Elke Scheer, University of Konstanz
  • Topic: Researching the physical mechanism of how voltage can be used to control superconductors, with the goal of developing an interfacing technology between superconductor and semiconductor technology for future supercomputers.
  • Project partners: University of Konstanz, CNR laboratories at Pisa and Salerno, Budapest University of Technology and Economics, Delft University of Technology, Chalmers University of Technology at Gothenburg, SeeQC-EU (Italy)