Evolution of ferroelectricity in ultrathin PbTiO3 films as revealed by electric double layer gating
Evolution of ferroelectricity in ultrathin PbTiO3 films as revealed by electric double layer gating
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双电层选通法研究PbTiO_3薄膜铁电性的演化
DOI：
10.1038/s41598-020-67580-8
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发表时间：
2020-07-02
影响因子：
4.6
通讯作者：
Kawasaki, Masashi
中科院分区：
文献类型：
--
作者：
Nishino, Ryutaro;Fujita, Takahiro C.;Kawasaki, Masashi
退极化场会使薄膜的铁电性失稳，导致自发极化降低或畴形成。在这里，在PbTiO 3膜中的剩余极化的厚度依赖性被电揭示到2.6 nm，通过控制极化方向，采用双电层门控技术，以抑制漏电流在PbTiO 3膜。对于17 nm厚的膜，剩余极化类似于体值，类似于60 μ C cm（-2），并且对于2.6 nm厚的膜，剩余极化降低到类似于20 μ C cm（-2），而在这样的非晶膜中清楚地观察到稳健的铁电性。原位X射线衍射测量下的外部电场揭示，减少四方性的x-rays膜主要是恢复抵消了退极化场。双电层选通技术是研究铁电薄膜物理性质的一种很好的方法。
Ferroelectricity in ultrathin films is destabilized by depolarization field, which leads to the reduction of spontaneous polarization or domain formation. Here, thickness dependence of remnant polarization in PbTiO3 films is electrically revealed down to 2.6 nm by controlling the polarization direction with employing an electric double layer gating technique to suppress leakage current in ultrathin films. The remnant polarization for a 17 nm-thick film is similar to bulk value similar to 60 mu C cm(-2) and reduces to similar to 20 mu C cm(-2) for a 2.6 nm-thick film, whereas robust ferroelectricity is clearly observed in such ultrathin films. In-situ X-ray diffraction measurements under an external electric field reveal that the reduced tetragonality in ultrathin films is mostly recovered by cancelling out the depolarization field. Electric double layer gating technique is an excellent way for exploring physical properties in ultrathin ferroelectric films.