Charge pumping in carbon nanotube quantum dots
  We investigate charge pumping in carbon nanotube quantum dots driven by the electric field of a surface acoustic wave. We find that at small driving amplitudes, the pumped current reverses polarity as the conductance is tuned through a Coulomb blockade peak using a gate electrode. We study the behavior as a function of wave amplitude, frequency and direction and develop a model in which our results can be understood as resulting from adiabatic charge redistribution between the leads and quantum dots on the nanotube. 
M.R. Buitelaar, V. Kashcheyevs, P.J. Leek, V.I. Talyanskii, C.G.   Smith, D. Anderson, G.A.C. Jones, J. Wei, D.H. Cobden