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Atomic-scale imaging finds a hidden twisted superlattice in long-ignored uranium oxytelluride
UT Dallas and Harvard physicists report in Nature a twisted superlattice in uranium oxytelluride, a compound known since the 1960s. Its mix of ferromagnetic and antiferromagnetic traits might one day help memory devices, if those advantages can be harnessed.
The Scientist · Science desk
What happened
- Sheng Ran of Washington University in St. Louis supplied the crystals, and Liu imaged them at the atomic scale with transmission electron and scanning tunneling microscopy.
- Electrons moving through the twisted structure behaved in unexpected ways, and further measurements pointed to the atomic arrangement as a key factor in how they travel.
- A Harvard group led by Suyang Xu was studying the same material at the same time, and the two teams regularly compared results from complementary experiments.
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Why it matters
- capability Materials searches gain a new criterion: superstructures larger than the basic atomic arrangement, a route Liu says can turn up compounds with unusual electron behaviour.
- constraint The memory case borrows advantages antiferromagnets have in general, so UOTe still has to show it can hold and switch a magnetic state before any device claim stands.
- precedent A compound left largely alone for about six decades showed a new structure under current microscopes, so re-imaging older catalogued materials becomes a reasonable bet for other groups.
"I was originally studying this material for an entirely different reason," Liu said [10]. "When I examined it with high-resolution microscopy, I found a naturally occurring superstructure no one had recognized before." [10] The work began while she was a Harvard Quantum Initiative postdoctoral fellow, before she joined the UT Dallas faculty in 2025 [12].
Chiral, in this case, means the repeating spirals twist mostly one way, either left-handed or right-handed [5]. The paper's title uses the field's own terms: "A chiral superlattice route to spin-split topological antiferromagnetism" [11]. The phys.org report puts it more plainly. Ferromagnets are magnetic while antiferromagnets have zero net magnetization, and according to the report UOTe shows characteristics of both [7][6]. "Finding a single material that combines both of these properties is interesting fundamentally," Liu said [13].
The study design matters here. A microscope image establishes that a superlattice exists, but it shows little about what electrons do inside it. That half came from pairing Liu's imaging with the Harvard experiments [8]. Further measurements, the report says, confirmed the atomic organization as "a key factor" governing how electrons travel through the crystal [9]. The wording is careful. It ties the structure to the electron behaviour without calling it the only cause. The report does not give the size of the effect or describe a test in any device.
The memory argument rests on what antiferromagnets generally offer. They resist disturbance from external magnetic fields better than conventional ferromagnets do, and they can operate faster [15]. Liu stated the application as a condition. "If those advantages can be harnessed, memory devices could potentially become both faster and more robust," she said [16].
The computational result could matter beyond this one compound. The team's analyses suggest hundreds of related compounds could host similar superlattice structures [17]. "Instead of focusing only on the fundamental atomic arrangement, we can also now explore larger superstructures that might influence how electrons behave," Liu said [18]. I think that search strategy is the more useful output for other labs, with one condition. A calculation yields candidates, and each one still needs the atomic-scale imaging that found the pattern in UOTe.
UOTe itself sat in the literature for about six decades before this paper [14]. "Uranium oxytelluride has been known since the 1960s, but it has been largely ignored in research since then," Liu said. "Now, with today's techniques, we're able to uncover and study properties that previously were hidden." [3]
What to watch
- Atomic-scale imaging of the related compounds the team's calculations flag, to see whether the predicted chiral superlattices actually appear.
- Published values for the size of the spin splitting in UOTe and the temperatures at which it holds.
- Any attempt to write and read a magnetic state in UOTe or a related compound, the first step toward the memory use Liu describes.