SURFACE AND DOMAIN-STRUCTURES OF FERROELECTRIC GASH CRYSTALS STUDIED BY SCANNING FORCE MICROSCOPY

Scanning force microscopy (SFM) has been used to study the (0001) cleavage faces of ferroelectric crystals of GASH (guanidinium aluminium sulfate hexahydrate). For the first time, the surface and domain structures of a ferroelectric material has been imaged directly from the micrometer down to the molecular scale. On the micrometer scale SFM reveals the elementary cleavage structure with typical zig-zag-shaped steps. Superimposed on this topographic structure are ferroelectric domain structures which could be imaged with SFM operating the force microscope in the repulsive contact mode. On the nanometer scale, molecular resolution has been achieved on the atomically flat terraces. The imaged surface lattice with spacings of 0.68 nm reflects the threefold symmetry of the unreconstructed GASH (0001) surface.