Plate Nº 18 · recorded October 8, 2026
PhysicsReported finding
Charge Stripes and Majorana Modes Meet Inside a Single Vortex
Atomic-scale imaging of an iron-based superconductor reveals charge stripes strengthening around vortex centers, where one vortex type hosts a Majorana zero mode.
By Marcus Bennett4 min read765 words
In brief
- The study was published in Physical Review Letters in 2026 (DOI: 10.1103/6f1z-dvc6).
- The material studied was Ba(Fe₀.₉₄Co₀.₀₆)₂As₂, with cobalt replacing 6% of iron sites.
- Researchers observed charge stripes intensifying around vortex centers, linked to two distinct vortex states.
- One vortex state hosted a zero-energy excitation identified as a Majorana zero mode.
- The team included researchers from Tsinghua University, Southern University of Science and Technology, and Boston College.
Physicists have observed, for the first time in this setting, charge stripes and two distinct types of vortex states — one hosting a Majorana zero mode — intertwined within single magnetic vortices of an iron-based superconductor. Their paper appeared in Physical Review Letters in 2026, with a preprint listed on arXiv (arXiv:2601.15873).
The team, led by researchers at Tsinghua University and Southern University of Science and Technology, together with colleagues at Boston College and other institutions, mapped the electronic landscape around vortices in thin films of cobalt-doped barium iron arsenide, Ba(Fe₀.₉₄Co₀.₀₆)₂As₂, with atomic-scale precision.
What exactly did they see?
Superconductors carry electric current with zero electrical resistance. In so-called type-II superconductors, magnetic fields can penetrate the material through thread-like regions called vortices. Each vortex carries a fixed amount of magnetic flux, with electrical currents circulating around its center.
Using spectroscopic-imaging scanning tunneling microscopy — a technique that moves an extremely fine tip just above a material's surface to map its electronic properties at different energies — the researchers found:
- Charge stripes: periodic modulations of electronic charge along one direction, which became stronger around vortex centers.
- Two distinct vortex states, distinguishable by where their centers sit relative to the stripe pattern.
- A zero-energy state in one of the two vortex types, which the researchers identified as a Majorana zero mode — a localized, zero-energy collective electronic excitation that behaves as a particle that is its own antiparticle.
Majorana zero modes interest quantum computing researchers because information stored across separated Majorana modes could, in principle, be protected against some local disturbances.
How did the discovery unfold?
The result was partly serendipitous. The team originally set out to look for vortex bound states and possible Majorana zero modes in 122-type iron pnictides — a family of iron-based superconductors.
"Our initial goal was to search for vortex bound states and possible Majorana zero modes in 122-type iron pnictides," said Can-Li Song, senior author of the paper. "Unexpectedly, we discovered charge stripes closely intertwined with different vortex states, which, with insights from our theoretical collaborators, became the central focus of this work."
"Our work grew out of our long-term effort to understand high-temperature superconductivity with atomic-scale precision," Song explained. "Magnetic vortices are particularly interesting because their cores provide a natural platform for exploring emergent electronic states in these unconventional superconductors."
First author Yu Liu described the method: the team grew optimally doped Ba(Fe₀.₉₄Co₀.₀₆)₂As₂ superconducting films by molecular beam epitaxy — a technique that builds a crystal layer by layer in high vacuum — and studied them with low-temperature scanning tunneling microscopy and spectroscopy. Cobalt replaced 6% of the iron sites in the crystal lattice.
"By mapping the electronic states around many vortices with atomic-scale precision, we identified charge stripes and two distinct types of vortex states, including those hosting Majorana zero modes, and revealed their intimate spatial correlation," Liu said.
Why does the intertwining matter?
The study establishes that electronic stripes and states bound at magnetic vortices in this specific iron-based superconductor are related. That relationship is the headline, according to co-author Xu-Cun Ma.
"The most exciting finding is that a Majorana zero mode, charge stripes, and a possible pair-density modulation all emerge within a single magnetic vortex and are intimately intertwined," Ma said. "This reveals how topology, charge order, and superconductivity can interact at the nanoscale."
A pair-density modulation is a periodic variation in the strength of the electron pairing that gives rise to superconductivity. Seeing all three phenomena — topology, charge order, and superconductivity — acting together inside one nanoscale object is what makes the observation notable.
What are the limits, and what comes next?
The findings come from one material system, observed with scanning probe microscopy at low temperature. Whether similar stripe-vortex relationships exist in other type-II superconductors remains an open question, and other research teams could now try to probe it.
The researchers themselves have a clear agenda. "We would now like to understand why charge stripes select different types of vortices, how they couple to Majorana states, and whether this intertwined behavior is universal across iron-based superconductors," Song said. "Ultimately, we hope to learn how these interactions can be used to control and manipulate Majorana zero modes."
In the long run, the team's observations could open new possibilities for controlling bound states in superconductors and inform efforts to manipulate Majorana zero modes — a step that matters for anyone hoping to build quantum technologies on top of them.
via Phys.org Physics (Source)
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