  Collective transport properties of a one-dimensional asymmetric periodic
substrate (1DAPS) modulated two-dimensional dusty plasma (2DDP) driven by an
unbiased sinusoidal excitation force are investigated using Langevin dynamical
simulations. It is discovered that, by changing the amplitude and frequency of
the unbiased sinusoidal external excitations, as well as the depth of 1DPAS,
both the direction and speed of the persistent particle flow can be adjusted,
i.e., both the flow rectification and its reversal of the ratchet effect of the
steady drift motion for particles are achieved using various excitations. For
the studied 2DDP under the 1DAPS, when the amplitude of the excitation
increases from zero, the magnitude of the overall drift velocity increases from
zero to its first maximum in the easy direction of the 1DAPS, next decreases
gradually back to zero, and then increases from zero to its second maximum in
the hard direction of 1DAPS before finally gradually decaying. It is found
that, as the frequency of the excitation and the depth of 1DAPS change, the
maximum overall drift velocity also varies, and the corresponding magnitude of
the excitation varies simultaneously. The observed ratchet effect in both the
easy and hard directions of 1DAPS for 2DDP is attributed to the combination of
the spatial symmetry breaking of 1DAPS and the inertial effects of particles,
which is further confirmed by the three different presented diagnostics.
