[en] Surface excitations, which can occur at the interface of an ionic crystal and a semiconductor superlattice in a transversal magnetic field, are investigated. It is shown that, under certain conditions, the propagation of a surface wave with frequencies lower than the electron cyclotron resonance frequency is possible. This mode has a negative group velocity. It is demonstrated that the resonance between surface polaritons and cyclotron oscillations of the electron system causes a small splitting of the surface polariton frequency. The behavior of the starting points of the surface coupling modes is also discussed. (author). 24 refs, 4 figs