Novel phases at domain walls

This chapter discusses how the intense stress fields generated at the ferroelastic domain walls in some epitaxially strained oxide layers introduce selective chemical modifications. This gives rise to novel 2D crystal structures at the walls. The chapter also describes a route for the stabilization of novel two-dimensional phases at structural domain walls that self-assembled during growth, driven by the large stresses present at the ferroelastic twin boundaries. In the case of strained TbMnO₃ films presented here, the substitution of Tb by Mn creates a net magnetic moment at each domain wall. This makes them distinct from the bulk-like antiferromagnetic domains. The possibility to tune the domain wall density with the film thickness brings forward a way to tailor the materials’ response at the nanoscale.