Electron microscopy is on the brink of a transition. Soon the imaging tool could be used to create structures atom by atom. This sort of control over atomic architecture could transform our basic scientific understanding of materials and pave the way to new classes of devices for quantum computing, spin sensing and more.
Currently, the only way to build at the atomic scale is with a scanning tunnelling microscope (STM). But this approach remains impractical and niche, 25 years after Don Eigler demonstrated it by spelling out the name of his company, IBM1. An STM can move only surface atoms and structures that are stable only at low temperatures. The technique is time-consuming and it requires bespoke machines. It can now make computing devices comprising several quantum bits (qubits), but not much more2.