  Picosecond switching of the staggered antiferromagnetic order is shown to be
realizable through spin-transfer torques from a short current pulse. The
coupled dynamics of sublattice magnetization is mapped onto a classical
pendulum subject to gravity and a driving pulse, where switching occurs if the
pendulum acquires sufficient kinetic energy during the pulse to overcome the
maximum of the effective gravity potential. The optimal switching scheme is
explored through the dependence of switch angle and magnetic loss on the
duration and strength of the current pulse. The physics discussed here provides
a general route towards multi-functional THz applications via the spin-transfer
torque in antiferromagnetic materials.
