Observation of ultrathin single-domain layers formed on LiTaO₃ and LiNbO₃ surfaces using scanning nonlinear dielectric microscope with submicron resolution

The formation of very thin domain layers on the surface of multidomain lithium tantalate by heat treatment is observed by scanning nonlinear dielectric microscopy. A similar phenomenon of forming a very thin single-domain layer was also observed on the surface of periodically polarized lithium niobate single crystal. By measuring the thickness of the single-domain layers, the depth sensitivity of the scanning nonlinear dielectric microscope with submicron resolution was estimated.