Wake Effects in Ion Transport through Carbon Nanotubes

A semiclassical kinetic model is explored to investigate the wake effects in the transport of charged particles through single-walled(SWCNT)and double-walled(2WCNTs)carbon nanotubes,with the introduction of electron band structure effect.The analytical expressions of the induced electron density at nanotube surface and the induced potential around the nanotube walls are obtained.The simulation results indicate that a bell-like distribution appears for the induced electron density when the incident particle speed is below a threshold value,otherwise wake-like oscillation can be seen behind the particle in the axial distribution.Dependencies of the amplitude and frequency of oscillations on the incident particle speed are also discussed.Meanwhile,we notice that the valence electrons on the outer wall of 2WCNTs tend to be easily excited by the polarized electrons on the inner wall,compared with that by the incident particle without the inner wall in SWCNTs.Finally,the induced potential trailing the incident particle also exhibits remarkable oscillations,not only along the axial direction but also in the lateral region,with evident extrema at the nanotube walls.