Oscillatory behavior of double-walled nanotubes under extension: A simple nanoscale damped spring

Computer simulations of double-walled carbon nanotubes show that if the inner nanotube is pulled out part of the way and then released, then the inner tube exhibits damped oscillatory behavior at gigahertz frequencies. A simple mathematical model, formulated in terms of macroscopic ideas of friction, is shown to predict the observed behavior to a high degree of accuracy.