標題: Possible absence of critical thickness and size effect in ultrathin perovskite ferroelectric films
作者: Gao, Peng
Zhang, Zhangyuan
Li, Mingqiang
Ishikawa, Ryo
Feng, Bin
Liu, Heng-Jui
Huang, Yen-Lin
Shibata, Naoya
Ma, Xiumei
Chen, Shulin
Zhang, Jingmin
Liu, Kaihui
Wang, En-Ge
Yu, Dapeng
Liao, Lei
Chu, Ying-Hao
Ikuhara, Yuichi
材料科學與工程學系
Department of Materials Science and Engineering
公開日期: 6-Jun-2017
摘要: 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 (similar to 4 nm). However, approximately the polarization never vanishes. The residual polarization is similar to 16 mu Ccm(-2) (similar to 17%) at 1.5-unit cells (similar to 0.6 nm) thick film on bare SrTiO3 and similar to 22 mu Ccm(-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.
URI: http://dx.doi.org/10.1038/ncomms15549
http://hdl.handle.net/11536/144074
ISSN: 2041-1723
DOI: 10.1038/ncomms15549
期刊: NATURE COMMUNICATIONS
Volume: 8
起始頁: 0
結束頁: 0
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