Interface localized modes and hybrid lattice solitons in waveguide   arrays
  We discuss the formation of guided modes localized at the interface separat- ing two different periodic photonic lattices. Employing the effective discrete model, we analyze linear and nonlinear interface modes and also predict the existence of stable interface solitons including the hybrid staggered/unstaggered lattice solitons with the tails belonging to spectral gaps of different types. 
M. I. Molina and Y. S. Kivshar