Condensed Matter Seminars

Some of the grand challenges in nanoscience are the ability to control movement of atoms either to propel nanometer-sized machines, or to synthesize novel electronic devices and materials. To that end, electrical current can be used to move a wide range of metals (Fe, Cu, W, In, Ga) along the outside and inside of a carbon nanotube. In this talk I will present a peculiar mechanism in which these metals move. For example, this mechanism allows an iron nanocrystal to pass through a constriction in the carbon nanotube with a smaller cross-sectional area than the nanocrystal itself. Remarkably, while passing through a constriction, the nanocrystal remains largely solid and crystalline and the carbon nanotube is unaffected. This behavior is accounted for by a pattern of iron atom motion and rearrangement on the surface of the nanocrystal. The nanocrystal motion can be described with a model whose parameters are nearly independent of the nanocrystal length, area, temperature, and electromigration force magnitude. I will also discuss implications of this work on synthesis of nanocomposite materials, and on the stability of carbon-based electronic devices.

More details can be found in these publications:

Phys. Rev. Lett. 110, 185901 (2013)
http://link.aps.org/doi/10.1103/PhysRevLett.110.185901

Phys. Rev. B 88, 045424 (2013)
http://link.aps.org/doi/10.1103/PhysRevB88.045424