Possible absence of critical thickness and size effect in ultrathin perovskite ferroelectric films
Open Access
- 6 June 2017
- journal article
- research article
- Published by Springer Science and Business Media LLC in Nature Communications
- Vol. 8 (1), 15549
- https://doi.org/10.1038/ncomms15549
Abstract
Although the size effect in ferroelectric thin films has been known for long time, the underlying mechanism is not yet fully understood and whether or not there is a critical thickness below which the ferroelectricity vanishes is still under debate. Here, we directly measure the thickness-dependent polarization in ultrathin PbZr0.2Ti0.8O3 films via quantitative annular bright field imaging. We find that the polarization is significantly suppressed for films −2 (∼17%) at 1.5-unit cells (∼0.6 nm) thick film on bare SrTiO3 and ∼22 μCcm−2 at 2-unit cells thick film on SrTiO3 with SrRuO3 electrode. The residual polarization in these ultrathin films is mainly attributed to the robust covalent Pb–O bond. Our atomic study provides new insights into mechanistic understanding of nanoscale ferroelectricity and the size effects.This publication has 38 references indexed in Scilit:
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