Observing the random diffusion of missing atoms in graphene

Imperfections in the regular atomic arrangements in crystals determine many of the properties of a material, and their diffusion is behind many microstructural changes in solids. However, imaging non-repeating atomic arrangements is difficult in conventional materials. Now, researchers at the University of Vienna have directly imaged the diffusion of a butterfly-shaped atomic defect in graphene, the recently discovered two-dimensional wonder material, over long image sequences. The results are published in the prestigious journal Nature. Atomic scale defects are always present in materials. For conventional materials they are hidden inside a large number of perfectly arranged atoms, except for at the surface. However, the situation is different in the case of low-dimensional materials like graphene.