  The dynamic behavior of the slip length in a fluid flow confined between
atomically smooth surfaces is investigated using molecular dynamics
simulations. At weak wall-fluid interactions, the slip length increases
nonlinearly with the shear rate provided that the liquid/solid interface forms
incommensurable structures. A gradual transition to the linear rate-dependence
is observed upon increasing the wall-fluid interaction. We found that the slip
length can be well described by a function of a single variable that in turn
depends on the in-plane structure factor, contact density and temperature of
the first fluid layer near the solid wall. Extensive simulations show that this
formula is valid in a wide range of shear rates and wall-fluid interactions.
