  We study the influence of transverse electric fields on the interfacial
forces between a graphene layer and a carbon nanotube tip by means of atomistic
simulations, in which a Gaussian regularized charge-dipole potential is
combined with classical force fields. A significant effect of the field-induced
electric charge on the normal force is observed. The normal pressure is found
to be sensitive to the presence of a transverse electric field, while the
friction force remains relatively invariant for the here-used field
intensities. The contact can even be turned to have a negative coefficient of
friction in a constant-distance scenario when the field strength reaches a
critical value, which increases with decreasing tip-surface distance. These
results shed light on how the frictional properties of nanomaterials can be
controlled via applied electric fields.
