Researchers from The University of Osaka successfully control the direction of current in a superconductor, creating a superconducting diode
Osaka, Japan – What would happen if you combined the unparalleled efficiency of a superconductor with the flexibility and controllability of a semiconductor? Thanks to a new breakthrough in quantum materials, we may be getting an answer soon.
In an article soon to be published in
Communications Physics, a multi-institutional research team led by The University of Osaka announces the successful observation of the so-called superconducting diode effect in an Fe(Se,Te)/FeTe heterostructure. The article describes a series of experiments in which the material developed a preference for current to flow in a particular direction, a phenomenon known as rectification, under a broad range of temperature and magnetic fields.
Essentially every electronic device in use today involves semiconductors, which can either inhibit or enhance the flow of electrons in one direction, allowing precise control over electrical signals. A longtime goal of physicists has been to merge this technology with superconductors, which have effectively no electrical resistance and can thus transport charges with perfect efficiency. However, to date, success has been limited.
“When it comes to superconductors, the choice of material is critical,” explains Junichi Shiogai. “Iron selenide telluride has ideal properties such as a high transition temperature, critical magnetic field, and critical current density. This means that the range of parameters for which the effect can appear is large, giving us the best chance for success.”
Indeed, when a magnetic field was applied to their system, there was a significant shift in current directionality. The effect also increased as the magnetic field strength was increased and as the temperature was decreased. By analyzing the data while these parameters were varied, the team was able to devise a coherent explanation for the effect.
“Until now, the mechanism of this effect has mostly been a mystery,” says Shiogai. “Our experiments reveal that the pinning of quantum vortices generated by the magnetic field plays a crucial role.”
The research team found that a strong spin-orbit interaction alters the asymmetric pinning potential so that vortices remain more stuck in one direction than the other, creating the breaking of symmetry needed to realize rectification. A strong linear correlation between the diode efficiency and the strength of polarization confirmed their hypothesis.
“We are optimistic that these results can be applied to develop an ideal rectification device that paves the way for ultra-low energy electronics built from superconductors,” says Shiogai. Thanks to the team’s research, the future of such superconductors is indeed looking bright.
###
The article, “A scaling relation of vortex-induced rectification effects in a superconducting thin-film heterostructure,” was published in
Communications Physics at DOI:
https://doi.org/10.1038/s42005-025-02118-w