Collective nonlinear electric polarization via defect-driven local symmetry breaking
| Autor: | Narendirakumar Narayanan, Yun Liu, Hua Chen, Aiping Chen, Lilit Jacob, Wen Dong, Xiaoyong Wei, Teng Lu, Terry J. Frankcombe, Wanbiao Hu, Qingbo Sun, Qian Li, David L Cortie, Dehong Yu, Mark G. Humphrey, Genmiao Wang |
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| Rok vydání: | 2019 |
| Předmět: |
Physics
Condensed matter physics Process Chemistry and Technology Poling 02 engineering and technology Dielectric 010402 general chemistry 021001 nanoscience & nanotechnology Polarization (waves) 01 natural sciences 0104 chemical sciences Condensed Matter::Materials Science Dipole symbols.namesake Polarization density Mechanics of Materials Local symmetry Electric field symbols General Materials Science Electrical and Electronic Engineering 0210 nano-technology Debye |
| Zdroj: | Materials Horizons. 6:1717-1725 |
| ISSN: | 2051-6355 2051-6347 |
| Popis: | In this work, we report the defect-mediated, abnormal non-linear polarization behavior observed in centrosymmetric rutile TiO2 where less than 1 at% of sterically mismatched Mg2+ ions are introduced to create ferroelectric-like polarization hysteresis loops. It is found that the defect cluster produces a dipole moment exceeding 6 Debye, with a rotatable component. Such a polarization is further enhanced by the displacement of neighboring Ti4+ ions. The coupling between such defect-driven symmetry-breaking regions generates a collective nonlinear electrical polarization state that persists to high temperatures. More importantly, an observation of abnormal bias shift of polarization hysteresis suggests an antiparallel alignment of certain dipoles frozen relative to the external poling electric field, which is associated with oxygen vacancy hopping. This result challenges the long-standing notion of parallel alignment of dipoles with the external electric field in ferroelectrics. This work also reveals an unexpected new form of non-linear dielectric polarization (non-ferroelectricity) in solid-state materials. |
| Databáze: | OpenAIRE |
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