A joint research team from the Shenyang National Laboratory for Materials Science at the Institute of Metal Research, Chinese Academy of Sciences (IMR, CAS) together with the Songshan Lake Materials Laboratory, has achieved a significant breakthrough in the precise control and real-time observation of atomic-scale structural transformations, a fundamental scientific challenge in the field of atomic-scale manufacturing.

The study, published in Advanced Materials, employs transmission electron microscopy to capture dynamic movements of tantalum atoms in KTaO₃ crystals and successfully induces a precise structural transformation into tungsten bronze K₆Ta₁₀.₈O₃₀, identifying key controlling parameters.

Using a scanning transmission high-energy electron beam, the researchers selectively "knocked out" potassium and oxygen atoms from KTaO₃ through controlled electron dose and displacement, generating vacancies that subsequently drove the migration of heavier tantalum atoms. This coordinated atomic motion ultimately transformed the material from a perovskite structure into a stable tetragonal tungsten bronze phase under ambient conditions.

"The work establishes an important scientific foundation for both 'precision fabrication' and 'clear observation' at the atomic scale," said the research team. "It reveals the atomic mechanisms of electron beam-induced atomic motion and structural transformation while pioneering a technical pathway for electron-beam-based atomic 'sculpting'."

Combined with low-dose phase-contrast imaging and density functional theory calculations, the team clearly elucidated the atomic migration pathways and underlying driving mechanisms, offering important theoretical and technical support for the atomic-level manufacturing of future functional oxide electronic devices.

(a) Structural schematic of KTaO₃ (b) Schematic of electron beam irradiation in STEM mode (c–l) Atomic motion and structural transformation under electron beam irradiation （Image by IMR）