  Recently, abundant transport phenomena characterizing the surface states of
Weyl semimetals (WSMs) have been reported. To generate these phenomena,
electrons have to complete a closed intersurface orbit. Due to the unavoidable
impurities in real materials, this orbit would be destroyed by the impurity
scattering, which limits the detection of the surface states in WSMs. Here, we
investigate the RKKY interaction between magnetic impurities, solely mediated
by a single surface band, in semi-infinite WSMs. It is found that peculiar
oscillations and slowly decaying laws of the RKKY interaction can act as the
signals to capture the dispersive nature of the surface states of WSMs. The
underlying physics is attributed to two effects: the band-edge effect and the
bending effect of the surface band, which can control the RKKY interaction
individually or compete with each other to produce more complex magnetic
behaviors. In addition, the band-edge effect together with the finite Fermi
energy would result in another interesting oscillation with battering pattern.
All the results are significantly different from that in previous literatures
where surface states have to couple with bulk states (or other surface states
of different spins) to generate nonzero magnetic interaction. Compared to the
previous models of surface states, the model here is more practical and is
helpful for the deeper understanding of the surface magnetic properties in
WSMs.
