Researchers at Delft University of Technology have managed to control the magnetism inside the nucleus of a single atom using radio waves. Until now, physicists assumed they could not directly manipulate nuclear spin. The finding could enable new ways to store and read quantum information. The study was published in Nature Communications.
Illustration of a single atom being manipulated using radio waves. Impression of the experiment where the spins of the electron (blue) and the nucleus (orange) within a single atom are independently controlled by wave signals from the probe tip of a tunneling microscope. Image Credit: Scixel
In metals like iron and nickel, each atom possesses a slight magnetic characteristic. However, within the atom, various magnetic “compass needles”, referred to as spins in the field of quantum mechanics, are also functioning.
By far the strongest magnetism comes from the electrons. But in some atoms, the nucleus also carries a spin. That spin is much weaker, but it is also much better shielded from the outside world.
Sander Otte, Study Lead Researcher, Delft University of Technology
Otte’s team studies spin using a modified scanning tunneling microscope built for this purpose. The setup lets them deliver electrical signals with extreme precision to a single atom. Until recently, the group focused mainly on electron spin because it is the most straightforward to measure. Nuclear spin, by contrast, was detected only indirectly through hyperfine interaction, which weakly couples the nucleus and electron spins and can leave them slightly entangled.
Control Against Expectations
Hester Vennema and colleagues applied two independent signals to a single atom at the same time: one tuned to act on the electron, the other targeted at the nucleus. That separation allowed them to isolate the effect of each signal. Using this approach, they could flip the nuclear spin even when the electron and nuclear spins were largely disentangled.
That result came unexpectedly.
According to our simple understanding, this should not really happen. The nuclear spin should not be sensitive at all to the electrical signals from a scanning tunneling microscope.
Sander Otte, Study Lead Researcher, Delft University of Technology
Guitar Strings
For this study, the team improved an established method called double magnetic resonance so they could apply it to a single atom. This made it possible to control the magnetism of the atomic nucleus separately from that of the surrounding electron.
In magnetic resonance, a wave signal changes the direction of a spin. Quantum mechanics shows that only specific rotations are allowed, meaning the signal has to match an exact resonance frequency.
You can compare it to the strings of a guitar. Each possible spin rotation is like a string with its own note. You have to play precisely the right note to make a particular string vibrate. The “notes” of a nuclear spin are a hundred to a thousand times lower than those of an electron spin.
Hester Vennema, Study Author, Delft University of Technology
Secure Quantum Information
The nuclear spin of atoms is especially important for secure quantum information storage. The ability to control nuclear spins could open new possibilities for storing and retrieving quantum information. Nonetheless, research has largely raised new questions about the mechanisms that influence nuclear spin.
“Back to the drawing board, then. That is really how science works. There is always something new left to figure out,” concluded Otte.
Journal Reference:
Vennema, H., G., et al. (2026) Nuclear magnetic resonance on a single atom with a local probe. Nature Communications. DOI:10.1038/s41467-026-78801-5. https://www.nature.com/articles/s41467-026-78801-5.