4 years ago

Possible absence of critical thickness and size effect in ultrathin perovskite ferroelectric films

Possible absence of critical thickness and size effect in ultrathin perovskite ferroelectric films
Ying-Hao Chu, Mingqiang Li, Bin Feng, Ryo Ishikawa, Naoya Shibata, En-Ge Wang, Dapeng Yu, Peng Gao, Shulin Chen, Xiumei Ma, Heng-Jui Liu, Yuichi Ikuhara, Zhangyuan Zhang, Kaihui Liu, Jingmin Zhang, Yen-Lin Huang, Lei Liao
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 <10-unit cells thick (4 nm). However, approximately the polarization never vanishes. The residual polarization is 16 μCcm−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.

Publisher URL: http://www.nature.com/articles/ncomms15549

DOI: 10.1038/ncomms15549

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.