  We show how a charge current through a single antiferromagnetic layer can
excite and control self-oscillations. Sustained oscillations with tunable
amplitudes and frequencies are possible in a variety of geometries using
certain classes of non-centrosymmetric materials that exhibit finite
dissipative spin-orbit torque. We compute the steady-state phase diagram as a
function of the current and spin-orbit torque magnitude. The anisotropic
magnetoresistance causes the conversion of the resulting AF oscillations to a
terahertz AC output voltage. These findings provide an attractive and novel
route to design terahertz antiferromagnetic spin-orbit torque oscillators in
simple single-layer structures.
