Resolving intrinsic dislocation structure in perovskite crystals using pulsed electron beam with atomic resolution

Plasticity is critical for processing semiconductors and ceramics and advancing flexible, deformable electronics. Perovskites like CsPbX₃ (X = Cl, Br, I) and SrTiO₃ exhibit remarkable room-temperature plasticity through {110} < 1 $\overline{1}$ 0> dislocations, yet their atomic structures remain unresolved. While theoretical models predict mobile, glide-dissociated dislocations, scanning transmission electron microscopy (STEM) observations often reveal sessile, climb-dissociated structures, inconsistent with their plasticity and high-temperature climb requirements. Here, employing electrostatic dose modulator (EDM)-based pulsed electron beams that maintain the original sub-angstrom resolution, we successfully resolved intrinsic, glide-dissociated dislocations in perovskites at atomic level. The beam-off intervals allow beam-induced point defects to recombine, thereby truncating the sustained period of peak defect concentrations. Switching to continuous beams instead triggers glide-to-climb transitions, where the climbed structures depend on core chemistry: anion-terminated dislocations form compact structures, while cation-terminated ones are extended. These findings elucidate the intrinsic dislocation structures and deformation mechanisms in perovskites, offering insights to other semiconductors/ceramics show similar climb-dissociation, like Al₂O₃. The EDM-based pulsed beam technique enables non-destructive, atomic-scale observation of beam-sensitive materials, also establishes a versatile platform for active nanostructure modulation, holding great potential for semiconductor defect engineering.