Determination of sign of surface charges of ferroelectric TGS using electrostatic force microscope combined with the voltage modulation technique

The sign of surface charges and the surface topography around a domain wall on a cleaved (010) surface of ferroelectric TGS [(NH2CH2COOH)(3) . H2SO4] were studied in air at room temperature. Using an electrostatic force microscope (EFM) combined Evil;hl;he voltage modulation technique, we determined the location of the domain wall and the sign of the surface charges around ii. At tile domain wall, ire found a ridge structure with a large peak in the spatial distribution of a feedback signal used to keep the amplitude of the 2 omega component of electric force constant. This means that the dielectric constant has a large peak valve at the domain wall. Furthermore, in an atomic force microscope (AFM) image in a contact mode, nle observed a small step 2-3 Angstrom high at the center of the domain wall.