  We investigate the possibility that the surface of a strongly coupled
electron-phonon system behaves differently from the bulk when the relevant
parameters are inhomogeneous due to the presence of the interface. We consider
parameter variations which make the surface either more metallic or more
insulating than the bulk. While it appears impossible to stabilize a truly
insulating surface when the bulk is metallic, the opposite situation can be
realized. A metallic surface can indeed be decoupled from a bipolaronic
insulator realized in the bulk.
