  We theoretically discover possible emergence of reentrant Walker breakdowns
for current-driven domain walls in layered antiferromagnets in striking
contrast to the unique Walker breakdown in ferromagnets. We reveal that the
Lorentz contraction of domain-wall width in antiferromagnets gives rise to
nonlinear current-dependence of the wall velocity and the predicted multiple
Walker breakdowns. The dominant efficiency of the current-induced staggered
spin-orbit torque over the spin-transfer torque to drive the domain-wall motion
is also demonstrated. These findings are expected to be observed in synthetic
antiferromagnets experimentally and provide an important contribution to the
growing research field of antiferromagnetic spintronics.
