Electromigration forces on ions in carbon nanotubes

Abstract

We calculate the electromigration forces on ions such as adsorbed alkali metal atoms in a carbon nanotube transistor. The forces are especially large in the turn-on regime of the transistor and much smaller in the off and on states. Electromigration in the channel is driven almost exclusively by the wind force. The sign of the "effective valence" Z* is independent of the actual charge sign but can be reversed with gate voltage, providing a dramatic illustration of the quantum character of the wind force. Our self-consistent nonequilibrium Green's function calculations treat a ballistic device within a tight-binding approximation. © 2005 The American Physical Society.