MORPHOLOGY AND STABILITY OF GROWING MULTIWALL CARBON NANOTUBES

We use ab initio and parametrized calculations to investigate the morp hology and structural stability at the growing edge of multiwall carbo n nanotubes. We find that these open-ended structures are stabilized a gainst dome closure by strong covalent bonds connecting the exposed ed ges of adjacent walls. Growth at the open edge involves rearrangement of these bonds, which are mediated by carbon atoms bridging the gap an d change the tip morphology significantly. Presence of a strong ''lip- lip'' interaction can explain formation of carbon nanotubes under anne aling conditions.