The mechanisms by which carbon nanotubule (CNT) proximal probe tips deform
during the indentation of surfaces are explored using classical molecular-d
ynamics simulations. The forces acting on the atoms in the simulations are
calculated using the Brenner empirical bond-order potential For hydrocarbon
s. The results show that open and capped single-walled CNT tips indented ag
ainst hydrogen-terminated diamond and graphene surfaces buckle and slip to
relieve the applied stress. The study also examines the indentation of capp
ed multiwalled tubules against: these surfaces to investigate the effect of
multiple shells on the deformation process. It is found that while shell-s
hell interactions have little effect on the deformation mechanisms, the mul
tiwalled tubule is significantly stiffer than comparably sized single-walle
d tubules. No bond formation between the shells is predicted as a result of
deformation. Finally, a small CNT rope is indented against diamond and gra
phene to assess the effect of intertubule interactions on deformation. The
simulations reveal how the deformation of the rope leads to the distortion
of its end and allow for the determination of the effect of shear stress wi
thin the bundle on the buckling force of the rope. [S0163-1829(99)03643-7].