Automated Software and High-Tilt Holders Push Atomic-Resolution Electron Tomography Into 3D Interface Imaging

Solid–solid interfaces and surfaces largely determine how materials behave, yet their three-dimensional atomic structures remain notoriously difficult to resolve. These regions are buried inside specimens, respond only weakly to probing beams, and are intrinsically non-periodic, which frustrates methods that rely on long-range crystallinity. Atomic-resolution electron tomography, or AET, offers a powerful route around this obstacle: by reconstructing three-dimensional atomic coordinates from a series of tilted images, it can determine local structure without requiring periodic crystals, making it especially suited to local, non-periodic and buried interfacial structures. But the technique has been held back by two persistent bottlenecks: low acquisition throughput and a lack of dynamic or in situ measurement capability. A team at Peking University now reports an integrated software–hardware framework designed to address both problems.

The research, led by Prof. Jihan Zhou at Peking University and published in Advanced Scientific Instruments, combines three elements: a standardized multi-metric strategy for evaluating reconstruction quality, an automated tilt-series acquisition platform called ZhouTomo, and newly designed high-tilt in situ holders for heating and cryogenic experiments. Together, the authors say, these advances outline a pathway toward automated, faster, more reliable and more dynamic three-dimensional atomic characterization of solid–solid interfaces.

The first element addresses the lack of standardized metrics across AET studies, which has made it difficult to compare results between groups. The team establishes a standardized evaluation strategy combining five complementary measures: Fourier shell correlation, the F1 score, root-mean-square deviation, projection-space residuals and a Zernike-based spherical symmetry metric. Together these provide a multi-level assessment of resolution, reproducibility, positional precision, data consistency and alignment accuracy.

The second element, ZhouTomo, is a visually guided automated acquisition platform that integrates microscope control, autofocus, target tracking and tilt-series acquisition in one system. In a demonstration on an aggregated platinum nanoparticle assembly, the software acquired a near-atomic-resolution HAADF-STEM tilt series fully automatically in about 1.5 hours, compared with the four to six hours typically required for manual operation. The reconstructed volume revealed nine single-crystalline platinum nanoparticles with Wulff-like polyhedral morphologies and distinct {100} and {111} surface facets.

The quality of the demonstration reconstruction is documented in detail. A volume rendering shows the full platinum nanoparticle aggregate, while a 1.4-angstrom-thick central slice through the reconstructed volume displays clear lattice fringes and internal voids within the particles. A surface rendering distinguishes {100} facets in yellow from {111} facets in blue, making the polyhedral geometry of each nanoparticle directly visible.

The third element tackles the dynamic dimension. The team designed and validated a high-tilt in situ heating holder that enables large-angle tilting, up to plus or minus 75 degrees, together with controlled heating inside the microscope. With this holder, the researchers tracked the thermally driven structural evolution of palladium–platinum core–shell nanoparticles from room temperature to 900 degrees Celsius, observing shell shrinkage, interfacial blurring and progressive alloying between the palladium and platinum — an atom-resolved view of how a bimetallic core–shell structure transforms under heat. The team also evaluated a commercial cryogenic holder for high-tilt atomic-resolution imaging, demonstrating its potential compatibility with AET data acquisition under cryogenic conditions.

The authors are explicit that this is a pathway rather than a finished endpoint. They note that integrating automated acquisition with physics-aware neural-network reconstruction and advanced in situ holders could extend AET to external-stimulus-driven experiments — thermal, electrical, electrochemical or gas-environment — and enable high-throughput statistical tomography of interfaces, defects and dynamic structural transformations. In such a scheme, the automated platform would feed large, consistent datasets to reconstruction algorithms that embed physical constraints, while purpose-built holders would deliver the stimuli that drive structures to evolve in real time inside the microscope.

The authors are also clear about what stands between the current demonstrations and broader application. Beyond metallic nanoparticles, extending AET to thin-film interfaces, battery materials and semiconductor heterojunctions will require further advances in specimen preparation, dose tolerance, light-element imaging and experimental control. The framework reported here does not solve those problems, but it defines acquisition and evaluation infrastructure on which such solutions will have to be built.

For a field in which a single tomographic experiment has traditionally consumed hours of hands-on microscope time and yielded reconstructions judged by ad hoc criteria, the combination of a 1.5-hour automated acquisition, a five-metric standardized evaluation protocol and holders that carry specimens from cryogenic conditions to 900 degrees Celsius marks a practical shift toward routine, quantitative, three-dimensional characterization of buried interfaces.

Subject of Research: Automated atomic-resolution electron tomography of solid–solid interfaces using automated tilt-series acquisition and high-tilt in situ holders

Article Title: Automated tilt-series acquisition and high-tilt in situ holders push atomic-resolution electron tomography toward quantitative 3D interface characterization

Article References: Automated tilt-series acquisition and high-tilt in situ holders push atomic-resolution electron tomography toward quantitative 3D interface characterization. Original publication (Bibliographic details unavailable.)

Image Credits: AI Generated

DOI: Not provided

Keywords: electron tomography, atomic resolution, solid–solid interfaces, automated acquisition, in situ heating, cryogenic holder, HAADF-STEM, platinum nanoparticles, core–shell nanoparticles, reconstruction quality metrics, Peking University, 3D atomic imaging