  Within the lattice dynamics formulation, we present an exact solution for
anti-plane surface waves in a square lattice strip with a surface row of
material particles of two types separated by a linear interface. The considered
problem is a discrete analog of an elastic half-space with surface stresses
modelled through the simplified Gurtin-Murdoch model, where we have an
interfacial line separating areas with different surface elastic properties.
The main attention is paid to the transmittance and the reflectance of a wave
across the interface. The presented results shed a light on the influence on
surface waves of surface inhomogeneity in surface elastic properties such as
grain and subgrain boundaries.
