  We show how a Dzyaloshinskii-Moriya interaction can be generated in an
ultrathin metal film from the induced internal electric field created by an
ultrashort electromagnetic pulse. This interaction does not require structural
inversion-symmetry breaking, and its amplitude can be tuned depending on the
amplitude of the field. We perform first-principles calculations to estimate
the strength of the field-induced magnetoelectric coupling for ferromagnetic
Fe, Co, and Ni, and antiferromagnetic Mn, as well as FePt alloys. Last, using
atomistic simulations, we demonstrate how an isolated antiferromagnetic
skyrmion can be coherently nucleated from the collinear background by an
ultrashort pulse in electric field on a 100-fs timescale.
