Electron Ptychography: Imaging Every Atom in Complex Materials

Understanding where every atom sits inside a material—and how those atoms move, interact, or become disordered—is essential for designing better batteries, catalysts, superconductors, and many other technologies. Yet this goal has remained out of reach, particularly for the lightest elements such as oxygen, lithium, and hydrogen, which are notoriously difficult to detect with conventional microscopy.

In this talk, I will introduce multislice electron ptychography (MEP), a new imaging approach that overcomes these long-standing limitations. By reconstructing how an electron beam scatters as it passes through a sample, MEP retrieves highly detailed 3D atomic structure and allow us to identify nearly every atom in the periodic table, including hydrogen, with unprecedented precision [1, 2].

I will highlight how this capability uncovers subtle features that were previously invisible, such as atomic-scale variations in hydrogen concentration within metal hydrides [3] and hidden patterns of oxygen point defects in complex nickelate superconductors [4,5]. I will also discuss how extending MEP to collect diffraction data from multiple viewing angles further enhances 3D atomic visibility, enabling us to pinpoint individual atoms in thick complex materials. Further extension could open a path to determining the full 3D atomic structure of delicate or amorphous materials that are inaccessible by traditional annular dark-field image-based atomic electron tomography techniques.