Physicists at the University of Regensburg (UR) led by the research groups of Professor Dr. Christoph Strunk / Dr. Nicola Paradiso and Professor Dr. Jaroslav Fabian made an exciting discovery: In their publication just published in Nature Nanotechnology, the research teams experimentally demonstrate a dramatic sign change of the supercurrent diode effect. The corresponding experimental data are in quantitative agreement with the theory of Dr. Andreas Costa, also a physicist at the University of Regensburg.

Most transistors, including the building blocks of computer's CPUs, generate heat. This is, because most conductors are resistive, leading to Joule heating. Indeed, there are special transistors which do not generate heat, the so-called "Josephson junction field effect transistors." They are based on the Josephson junction, a weak connection between two superconductors, which still carries a zero-resistance current (or supercurrent).

After its discovery by Nobel Prize winner Brian Josephson, Josephson junctions quickly found applications in various fields such as medicine, metrology, and astrophysics. More recently, they became key components of quantum computers, since they are at the heart of transmons, the most popular qubit implementations in superconducting quantum processors.

In light of the above, one can understand the attention generated by the discovery of the first superconducting based on a Josephson junction made in 2021 in the group led by Nicola Paradiso and Christoph Strunk at the University of Regensburg in a synthetic crystal grown by Michael J. Manfra and his team at Purdue University.

The excitement arises from the potential for superconducting diodes to serve as the basic building blocks for new types of superconducting circuits, for a future replacement of resistive circuits by superconducting ones.

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