Metadislocation core structure and atomic model for metadislocation motion

We have analyzed the atomic structure of a metadislocation core using aberration-corrected high-resolution electron microscopy. It is shown that the metadislocation core is highly ordered and based on atomic clusters. It possesses a multiscale structure with an inner core comprising the full strain of the metadislocation, and an outer core which is not strained but has a cluster structure modified with respect to the bulk. We have developed the first atomic model for metadislocation motion based on repetitive jump patterns along various crystallographic directions. It involves the movement of about 100 atomic positions per step of metadislocation motion. Characteristic parallel “paired jumps” of neighboring atomic columns lead to a net flux of atoms towards the metadislocation core which is consistent with the negative climb mode of metadislocation motion.