Direct Observation of Huge Flexoelectric Polarization around Crack Tips.
basic_science · Level V
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- Record sourced from PubMed, PMID 31851827.
- Also identified by DOI 10.1021/acs.nanolett.9b03176.
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Abstract
Flexoelectricity is especially relevant for nanoscale structures, and it is expected to be largest at the tip of cracks. We demonstrate the presence of a huge flexoelectric polarization at crack tips in SrTiO<sub>3</sub> by direct observation with scanning transmission electron microscopy. We observe an averaged polarization of 62 ± 16 μC cm<sup>-2</sup> in the three unit cells adjacent to the crack tip, which is one of the largest flexoelectric polarizations ever reported. The polarization is screened by an electron density of 0.7 ± 0.1 e<sup>-</sup>/uc localized within one unit cell. These findings reveal the relevance of flexoelectricity for the science of crack formation and propagation.