Recent results have demonstrated an exceptionally high dielectric constant in the range 200 K-330 K in a crystalline tianium oxide : Rb2Ti2O5. In this article, the possibility of a structural transition giving rise to ferroelectricity is carefully inspected. In particular X-Ray diffraction, high resolution transmission electron microscopy and Raman spectroscopy are performed. The crystal structure is shown to remain invariant and centrosymmetric at all temperatures between 90 K and 450 K. The stability of the C2/m structure is confirmed by DFT calculations. These important findings allow to discard the existence of a conventional ferroelectric phase transition as a possible mechanism for the unusual dielectric constant observed in this material.
@article{arxiv.1703.04657,
title = {The crystal structure of Rb2Ti2O5},
author = {R. Federicci and B. Baptiste and F. Finocchi and A. F. Popa and L. Brohan and K. Beneut and P. Giura and G. Rousse and A. Descamps-Mandine and T. Douillard and A. Shukla and B. Leridon},
journal= {arXiv preprint arXiv:1703.04657},
year = {2017}
}
Comments
23 pages with appendixes. 21 figures with appendixes. 9 figures in the main text