“…This is why much effort has been spent in computing the elastic energy induced by periodic distribution of dislocations; we refer to the monograph [23, Sec 3.3] for a comprehensive overview. A relevant theoretical question is to understand optimal configurations of dislocations without assuming their periodicity: rigorous proofs that dislocations are favorable with respect to purely elastic deformations for large interfaces, as well as energy scaling properties have been recently faced in a variety of physical systems related to grain boundaries and epitaxial growth, starting from discrete or semi-discrete models of dislocations [2,3,6,7,9,10,13,[15][16][17][18]21]. The goal of this paper is to analyze the simplified version of the Peierls-Nabarro model, based on the minimization of the energy in (1), without assuming any periodicity on u.…”