  We present a theoretical study on nucleation and propagation of
antiferromagnetic skyrmionium induced by spin current injection. A skyrmionium,
also known as 2{\pi} skyrmion, is a vortex-like magnetic structure
characterized by a topological charge, the so-called skyrmion number, being
zero. We find that an antiferromagnetic skyrmionium can be generated via a
local injection of spin current with toroidal distribution. A spatially uniform
spin current is then demonstrated to induce a propagation of the skyrmionium.
We derive an expression for the skyrmionium velocity based on a
collective-coordinate model, which agrees well with our numerical results. Our
findings suggest a novel way of nucleating an antiferromagnetic skyrmionium, as
well as an analytical estimation of the current-driven skyrmionium velocity.
