DEFORMATION OF CRYSTAL-SURFACES IN FERROELASTIC MATERIALS CAUSED BY ANTIPHASE DOMAIN BOUNDARIES

The internal stresses occurring around domain walls can cause deformat ion of the crystal surface. The surface distortions have been calculat ed for the case of antiphase boundaries in tetragonal crystals. In KSC N a bump-shaped deformation of the surface occurs, with a height less than 1 Angstrom. This effect is much smaller in Hg2Br2 but, besides a bump, a valley can also appear depending on the orientation of the ant iphase boundary. The antiphase boundaries, the observation of which is difficult, could be revealed by such deformations of the crystal surf ace.