Researchers at The University of Osaka have stabilized a unique cobalt-based honeycomb structure within a layered material, potentially offering a cost-effective pathway toward building quantum technologies. By introducing a small amount of cobalt into sodium antimonate (NaSbO3), the team demonstrated a new platform for studying Kitaev materials, sidestepping the need for rare and expensive metals like ruthenium and iridium. These cobalt atoms form local honeycomb arrangements inside a larger honeycomb matrix, exhibiting strong magnetic interactions crucial for quantum computing applications; unlike typical liquids, the arrangement of spin remains fluid even as temperatures drop due to constantly flipping magnetic forces. “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.”
Cobalt-Doped NaSbO3 Creates Stable Honeycomb Structures
By incorporating approximately 4% cobalt into sodium antimonate (NaSbO3), a compound already possessing a honeycomb lattice, the team created a thin-film material exhibiting strong magnetic interactions essential for quantum computing applications. This approach diverges from reliance on scarce and costly metals traditionally used in this field. Careful microscopy confirmed the stability of the honeycomb arrangement, preventing the formation of undesirable secondary phases during material creation, a critical step toward practical application. This work addresses a key limitation in the development of Kitaev materials, a class of quantum magnetic materials studied for their potential in quantum information science, which often rely on rare elements. The resulting cobalt honeycomb motifs demonstrate ferromagnetic-like ordering at low temperatures, a crucial characteristic for manipulating quantum states; the team observed this behavior around 88 K, indicating a potential operating range for future devices.
Theoretical calculations suggest these magnetic properties arise from the tendency of cobalt atoms to cluster locally, forming edge-sharing CoO6 honeycomb motifs within the larger structure. “What excites us is that these cobalt honeycombs appear to form naturally, without any special coaxing,” explains senior author Hidekazu Tanaka, emphasizing the relative ease of creating this complex structure. “Cobalt is relatively cheap, widely available, and already used in semiconductor manufacturing,” remarks Li, suggesting that this material could lead to quantum computing components that are far more practical to produce at scale, potentially accelerating the development of this technology.
Ferromagnetic-like Ordering Emerges at 88K in Cobalt Honeycombs
This achievement, recently detailed in Physical Review Materials, signifies a shift toward more accessible materials for advanced technologies. The significance of this work extends to the study of Kitaev materials, which are investigated for their potential to host exotic quantum states known as spin liquids; in these materials, spin arrangement remains fluid even at low temperatures due to constantly flipping magnetic moments unable to satisfy competing forces. Magnetic measurements revealed a ferromagnetic-like state within the compound at approximately 88 Kelvin, a temperature at which many materials typically transition to ordered magnetic states.
This approach could eventually lead to quantum computing components that are far more practical to produce at scale.
