Scientists in Japan have discovered that steps just one atom high can act as microscopic rails, guiding the movement of quantum vortices inside an ultrathin superconductor. Under certain conditions, these vortices moved along the steps more than 1000 times more easily than across them. The researchers also found that this remarkable effect can be tuned simply by changing the temperature or the magnetic field.
The discovery was made by scientists at the Research Center for Materials Nanoarchitectonics (MANA) of Japan's National Institute for Materials Science (NIMS). Their results offer a promising new approach for controlling quantum behavior and could eventually help engineers build superconducting electronics that use far less energy while processing information more efficiently.
Superconductors are extraordinary materials that, when cooled below a critical temperature, can transmit electricity without electrical resistance. This property makes them attractive for developing highly energy-efficient electronics and other advanced technologies. However, superconductors also contain tiny quantum structures—so-called vortices—that form where magnetic fields penetrate the material, creating small regions surrounded by circulating electric currents. When vortices move, they can generate electrical resistance and affect the superconductor's performance. Until now, directing their motion in ultrathin, two-dimensional superconductors has been particularly difficult.
This result matters not because superconductors are new in themselves, but because of what it says about control. The movement of quantum vortices has until now been a process that was hard to guide, especially in ultrathin superconductors, and it is precisely this movement that causes energy loss. If atomic steps can become predictable pathways, then this changes the framing of the question of how losses can be reduced in superconducting devices.
Also noteworthy is that the effect is tuned by temperature and magnetic field rather than by changing the material's chemical composition. In practice, this means the same device could operate in different regimes without being redesigned, which is a serious advantage for engineers. It is not yet clear how well this approach will work in larger and more complex devices, but the direction itself is worth following.
