Kelvin probe force microscopy of periodic ferroelectric domain structure in KTiOPO4 crystals

Mono- and periodically poled domain structures of ferroelectric KTiOPO4 crystals have been studied by Kelvin probe force microscopy. This scanning probe method has allowed us to image the domain structure using a contact potential difference contrast between 180degrees ferroelectric domains. The measured contact potential difference between adjacent domains showed that the screening in the KTiOPO4 crystals is provided by the highly mobile potassium ions. The screening charge density distribution and the resulting Debye length near the polar faces have been estimated.