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The controlled transport of various masses along carbon nanotubes used as electric wires is another interesting possibilty for the developpement of nanotechnologies. We present a theoretical study of the forces acting on atoms adsorbed on carbon nanotubes when an electric current is present. Our simulations are based on the Non-Equilibrium Green's Functions approach (NEGF) that relies on Density Functional Theory calculations. The technique allows the determination of the electronic structure of a nanotube and predict how it will be modified by an applied bias voltage. The technique was applied on a metallic (5,5) carbon nanotubes supporting various atoms (B, C, N, O or F). The forces created on the adatoms were calculated and we observe they push the negatively charged atoms (N, O, F) in the direction of the electrons flow and positively charged atoms (B, C) in the opposite direction. A stronger force, perpendicular to the CNT surface, is independent of the current direction: it pushes C,N,O and F away from the tube's surface but pulls B closer to it. We explain the unexpected features of the current-induced forces from a chemical point of view. showing how the applied bias will populate and depopulate the scattering states neighbouring the Fermi level. |