Coulomb blockade ratchet pumping induced by surface acoustic waves in carbon nanotubes

Abstract

We have observed net electron transport at zero bias, induced by surface acoustic wave (SAW), through a double-walled carbon nanotube on top of a GaAs substrate. As gate voltage varied, the SAW-induced current showed quasiperiodic oscillations ranging from positive to negative values. Such zero-bias oscillations were found to be closely related with the Coulomb oscillation at finite bias. SAW-induced ratchet pumping could explain our observations.