title: Surface gap solitons.
abstract: We put forward the existence of surface gap solitons at the interface between uniform media and an optical lattice with defocusing nonlinearity. Such new type of solitons forms when the incident and reflected waves at the interface of the lattice experience Bragg scattering, and feature a combination of the unique properties of both surface waves and gap solitons. We discover that gap surface solitons exist only when the lattice depth exceeds a threshold value, that they can be made completely stable, and that they can form stable bound states.
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, Universitat Politecnica de Catalunya, Mediterranean Technology Park, 08860 Castelldefels (Barcelona), Spain.
authors.forename: Yaroslav V
authors.initials: YV
authors.lastname: Kartashov
authors.forename: Victor A
authors.initials: VA
authors.lastname: Vysloukh
authors.forename: Lluis
authors.initials: L
authors.lastname: Torner