Shallow Pb3+ hole traps in lead zirconate titanate ferroelectrics

A combination of electron paramagnetic resonance and band structure calculations is used to show that the Pb2+ ions in lead zirconate titanate materials can act as shallow hole traps to give Pb3+ centers. The Pb3+ centers are created by optical illumination and are found to be metastable at room temperature. Their decay kinetics follow a stretched exponential function which suggests dispersive transport. The traps have the same character as the upper valence band which is formed from the hybridization of Pb s and O p states.