We used time-of-flight scattering and recoiling spectrometry to study the surface of a LiTaO3 (0001̄) single crystal as a function of temperature (22–200 °C). We found that the variations in surface voltage induced by pyroelectric changes of spontaneous polarization could be quantitatively estimated by computing the effects of surface voltage on the ion optics and scattering events, and measuring scattering and recoiling spectral peak shifts. Generally, when LiTaO3 (0001̄) in a steady state at room temperature was probed, its negative spontaneous polarization charge was compensated by an equivalent amount of positive surface charge and the surface voltage was virtually zero. Raising the sample temperature reduced the spontaneous polarization and indeed a rising positive surface voltage was recorded, which shows that the positive surface charge could not be drained out from the insulating surface instantaneously. However, above 160 °C, the surface voltage returned to around zero, which indicates the presence of a thermally induced surface charge compensation mechanism on LiTaO3 (0001̄) above 160 °C. Cooling the sample both closed this surface charge compensation channel and increased the negative spontaneous polarization charge. A rising negative surface voltage, which is a proper pyroelectric response, was experimentally recorded. However, the spectral changes in the cooling cycle were rather complex. First, peak shifts did not follow the theoretical pyroelectric changes, and second, unexpected additional peaks were observed. These spectral behaviors are attributed to the presence of enhanced ion induced electron and negative ion emission as additional surface charge compensation mechanisms which modified the pyroelectric changes of surface voltage on LiTaO3 (0001̄). In addition, these surface properties were found to be sensitive to surface treatments such as sputtering and proton exchange.
