A research team at MANA/NIMS has demonstrated that single-atom-high surface steps on ultrathin superconductors act as directional rails, guiding superconducting vortices along the steps with greatly reduced resistance compared to across them.

Experimentally, one-atom-high steps channel magnetic flux and local heat flow in nanoscale circuits, offering a pathway to ultralow-power computation and more efficient quantum information processing.

At the atomic scale, these steps serve as effective rails for controlling vortex motion and heat flow in future superconducting technologies.

The findings were reported in Physical Review B on July 30, 2026, with Takashi Uchihashi and colleagues from MANA/NIMS as authors.

The context situates the work within the broader MANA/WPI research ecosystem, linking to related highlights and resources.

Vortices move along the steps more than 1,000 times more easily than across them at intermediate magnetic fields, illustrating strong directional control.

Experiments showed massive transport anisotropy, with vortex transport parallel to the steps vastly exceeding transverse motion at intermediate fields.

Scanning tunneling microscopy confirmed vortices located along the parallel atomic steps, evidencing the rail-like guiding effect.

The study used an atomic-layer superconductor grown on vicinal surfaces with parallel, regularly arranged atomic steps and visualized vortices along these steps via STM.

At the lowest temperatures, vortex transport shifts from thermally activated motion to quantum tunneling along the steps, and guiding efficiency can be tuned by adjusting magnetic field and temperature.

Four-terminal resistance measurements reveal directional anisotropy, with a near pinning-free one-dimensional flow between about 0.10 and 0.20 T along the steps, transitioning to quantum tunneling at the lowest temperatures.

Overall, the work points to potential ultralow-power superconducting devices and enhanced processing efficiency through controlled vortex dynamics.