  We investigate the formation and dynamics of spin textures in
antiferromagnetic insulators adjacent to a heavy-metal substrate with strong
spin-orbit interactions. Exchange coupling to conduction electrons engenders an
effective anisotropy, Dzyaloshinskii-Moriya interactions, and a magnetoelectric
effect for the N\'{e}el order, which can conspire to produce nontrivial
antiferromagnetic textures. Current-driven spin transfer enabled by the heavy
metal, furthermore, triggers ultrafast (THz) oscillations of the N\'{e}el order
for dc currents exceeding a critical threshold, opening up the possibility of
Terahertz spin-torque self-oscillators. For a commonly invoked
antidamping-torque geometry, however, the instability current scales with the
energy gap of the antiferromagnetic insulator and, therefore, may be
challenging to reach experimentally. We propose an alternative generic geometry
for inducing ultrafast autonomous antiferromagnetic dynamics.
