Surface structure of domain walls

The results of a numerical simulation of the surface structure of an orthogonally intersecting twin domain wall in a ferroelastic lattice are presented. The twin wall is seen at the surface as a pitched roof structure. The centre of the wall appears as a rounding of the ridge. The thickness of the ridge is the same as the thickness of the twin domain wall in the bulk. In contrast to this simple shape of the relaxed surface, the elastic response is rather exotic. We predict that AFM images taken in tapping mode should show a narrow groove at the middle of the ridge with two hill-like features on either side of the groove. Consequences for the chemical activity of the sites close to the ridge are discussed.