Researchers have created a cobalt-based thin film that could offer a lower-cost approach to developing materials for quantum research. By adding about 4% cobalt to sodium antimonate, scientists created localized honeycomb structures that produce strong magnetic interactions associated with Kitaev-type quantum materials without disrupting the material’s larger crystal structure.
Kitaev materials are studied because some may support quantum spin liquids, unusual states in which atomic spins remain dynamic instead of settling into conventional magnetic order. Research has often relied on compounds containing scarce metals such as ruthenium and iridium.
“Previous work in this area has largely been limited to rare metals like ruthenium and iridium,” says lead author Hao-Bo Li. “We asked whether cobalt, one of the most common transition metals on Earth, could be made to form the same honeycomb structure and display the same intriguing physics.”
Microscopy confirmed that the cobalt atoms clustered into the predicted honeycomb motifs without creating unwanted secondary phases.
“What excites us is that these cobalt honeycombs appear to form naturally, without any special coaxing,” explains senior author Hidekazu Tanaka. “They even produce a clear magnetic signal that matches what theory predicts for this type of structure.”
Magnetic measurements showed a ferromagnetic-like state near 88 K, or about minus 301 degrees Fahrenheit. Calculations indicate that this behavior comes from the local arrangement of cobalt atoms within the CoO6 structures.
The material has not been shown to host a quantum spin liquid, but it provides a cobalt-based system for studying Kitaev-type magnetism without relying on rare metals.
“Cobalt is relatively cheap, widely available, and already used in semiconductor manufacturing,” remarks Li. “This approach could eventually lead to quantum computing components that are far more practical to produce at scale.”
The researchers are now working to further engineer the material and test its quantum properties in greater detail.
For more information: Physical Review Materials
