About the nature of two-dimensional formations at the polar surface of cleaved triglycine sulfate crystals

Abstract

Fine structure of the (010) polar surface of triglycine sulfate crystal has been investigated by atomic force microscopy in contact and resonant (tapping) modes at room temperature and after heating. It has been shown that the round islands and holes of nanometer lateral size and height (depth) of ½ b (0.63 nm) occur only at atomic-smooth regions of the surface of the crystal cleaved in ferroelectric phase; and they are characteristic steady details of its microrelief. They conserve their geometrical sizes at heating above the Curie temperature, existing irrespective of domain structure and direction of the polarization vector, but they can change under influence of mechanical stress. It has been revealed that repeated scanning of mono domain regions of the surface in contact mode and shock influence in resonant mode result in occurrence of characteristic round islands and holes of the nanometer lateral size and height (depth) about ½ b.