Atomic-Scale Measurement of Flexoelectric Polarization at SrTiO3 Dislocations

Owing to the broken translational symmetry at dislocations, a strain gradient naturally exists around the dislocation cores and can significantly influence the electrical and mechanical properties. We use aberration corrected scanning transmission electron microscopy to directly measure the flexoelectric polarization (similar to 28 mu C cm(-2)) at dislocation cores in SrTiO3. The polarization charges can interact with the non-stoichiometric dislocation cores and thus impact the electrical activities. Our findings can help us to understand the properties of dislocations in perovskite, providing new insights into the design of new devices via defect engineering such as bicrystal fabrication and thin film growth.