  The existence of the magnetostatic surface spin waves in ferromagnets, known
as Damon-Eshbach mode, was recently demonstrated to originate from the topology
of the dipole-dipole interaction. In this work, we study the topological
characteristics of magnons in easy-axis antiferromagnets with uniaxial
anisotropy. The dipolar spin waves are found to be, driven by the dipole-dipole
interaction, in a topological nodal-line semimetal phase, which hosts
Damon-Eshbach-type surface modes due to the bulk-edge correspondence. The long
wavelength character of dipolar spin waves makes our proposal valid for any
natural uniaxial easy-axis antiferromagnet, and thus enriches the candidates of
topological magnonic materials. In contrast to the nonreciprocal property in
ferromagnetic case, the surface modes with opposite momentum coexist at each
surface, but with different chiralities. Such a chirality-momentum or
spin-momentum locking, similar to that of electronic surface states in
topological insulators, offers the opportunity to design novel chirality-based
magnonic devices in antiferromagnets.
