A giant atomic slide-puzzle

摘要

Atoms in close-packed surfaces of metal crystals move around at surprisingly high rates, even though each atom is locked in tightly by its neighbours. Here we use a low density of indium atoms, embedded in the outermost atomic layer of a copper surface, as tracer particles for scanning tunnelling microscopy to reveal the high vacancy-assisted mobility of atoms in this surface. We believe that most close-packed surfaces of metals and other materials will exhibit a similar vacancy-assisted motion at room temperature, with such surfaces behaving like a gigantic atomic slide-puzzle.