Rb2Ti2O5 : Superionic conductor with colossal dielectric constant
Abstract
Electrical conductivity and high dielectric constant are in principle self-excluding, which makes the terms insulator and dielectric usually synonymous. This is certainly true when the electrical carriers are electrons, but not necessarily in a material where ions are extremely mobile, electronic conduction is negligible, and the charge transfer at the interface is immaterial. Here we demonstrate in a perovskite-derived structure containing five-coordinated Ti atoms, a colossal dielectric constant (up to 109) together with very high ionic conduction 10-3Scm-1 at room temperature. Coupled investigations of I -V and dielectric constant behavior allow us to demonstrate that, due to ion migration and accumulation, this material behaves like a giant dipole, exhibiting colossal electrical polarization (of the order of 0.1Ccm-2 ). Therefore it may be considered as a "ferro-ionet" and is extremely promising in terms of applications.
- Publication:
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Physical Review Materials
- Pub Date:
- August 2017
- DOI:
- 10.1103/PhysRevMaterials.1.032001
- arXiv:
- arXiv:1703.01422
- Bibcode:
- 2017PhRvM...1c2001F
- Keywords:
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- Condensed Matter - Materials Science
- E-Print:
- 4 figures, one file of supplemental material