  We study both analytically and numerically the edge of two-dimensional
ferromagnets with Dzyaloshinskii-Moriya (DM) interactions, considering both
chiral magnets and magnets with interface-induced DM interactions. We show that
in the field-polarized ferromagnetic phase magnon states exist which are bound
to the edge, and we calculate their spectra within a continuum field theory.
Upon lowering an external magnetic field, these bound magnons condense at a
finite momentum and the edge becomes locally unstable. Micromagnetic
simulations demonstrate that this edge instability triggers the creation of a
helical phase which penetrates the field-polarized state within the bulk. A
subsequent increase of the magnetic field allows to create skyrmions close to
the edge in a controlled manner.
