Domain polarity and temperature induced potential inversion on the BaTiO3(100) surface

Variable temperature scanning surface potential microscopy is used to determine thermodynamic and kinetic parameters associated with polarization screening on ${\mathrm{BaTiO}}_3\text{(100)}$ surfaces. The temperature dependence of the surface potential is indicative of the interplay between the fast dynamics of atomic polarization and slower dynamics of screening charge. The screening charge relaxation kinetics are found to be weakly dependent on temperature with activation energy $E_a\text{∼4\hspace{0.05em}}\mathrm{kJ/mole}.$ Equilibrium domain potential difference depends linearly on temperature; the zero potential contrast is observed at ∼110 °C. At room temperature the sign of domain potential is determined by the screening charges rather than polarization charge. A thermodynamic model for screening of ferroelectric surfaces based on Ginzburg–Devonshire theory is developed so that the enthalpy and entropy of charge compensation can be derived from the temperature dependence of surface potential contrast. In the case of ${\mathrm{BaTiO}}_3$ in air, the charge compensation mechanism is surface adsorption.