Chen Zibin, Li Fei, Huang Qianwei, Liu Fei, Wang Feifei, Ringer Simon P, Luo Haosu, Zhang Shujun, Chen Long-Qing, Liao Xiaozhou
School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006, Australia.
Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, Xi'an Jiaotong University, Xi'an 710049, China.
Sci Adv. 2020 Oct 14;6(42). doi: 10.1126/sciadv.abc7156. Print 2020 Oct.
Thickness effect and mechanical tuning behavior such as strain engineering in thin-film ferroelectrics have been extensively studied and widely used to tailor the ferroelectric properties. However, this is never the case in freestanding single crystals, and conclusions from thin films cannot be duplicated because of the differences in the nature and boundary conditions of the thin-film and freestanding single-crystal ferroelectrics. Here, using in situ biasing transmission electron microscopy, we studied the thickness-dependent domain switching behavior and predicted the trend of ferroelectricity in nanoscale materials induced by surface strain. We discovered that sample thickness plays a critical role in tailoring the domain switching behavior and ferroelectric properties of single-crystal ferroelectrics, arising from the huge surface strain and the resulting surface reconstruction. Our results provide important insights in tuning polarization/domain of single-crystal ferroelectric via sample thickness engineering.
诸如薄膜铁电体中的应变工程等厚度效应和机械调谐行为已得到广泛研究，并被广泛用于调整铁电性能。然而，在独立单晶中情况并非如此，由于薄膜和独立单晶铁电体在性质和边界条件上的差异，薄膜的结论无法复制。在这里，我们使用原位偏置透射电子显微镜研究了厚度依赖的畴切换行为，并预测了表面应变诱导的纳米级材料中铁电性的趋势。我们发现，样品厚度在调整单晶铁电体的畴切换行为和铁电性能方面起着关键作用，这是由巨大的表面应变和由此产生的表面重构引起的。我们的结果为通过样品厚度工程调整单晶铁电体的极化/畴提供了重要见解。
