Abstract
The existence of a new class of localized structures in nonlinear lattices is proved analytically and it is pointed out that such excitations have been recently observed experimentally [B. Denardo et al., Phys. Rev. Lett. 68, 1730 (1992)] in the form of the so-called ‘‘noncutoff kinks.’’ These localized structures appear to be due to nonlinearity-induced breaking of symmetry between two equivalent eigenmodes of the lattice, and they probably exist in a large variety of nonlinear discrete systems.