Lee J W, Eom K, Paudel T R, Wang B, Lu H, Huyan H X, Lindemann S, Ryu S, Lee H, Kim T H, Yuan Y, Zorn J A, Lei S, Gao W P, Tybell T, Gopalan V, Pan X Q, Gruverman A, Chen L Q, Tsymbal E Y, Eom C B
Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA.
Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE, 68588, USA.
Nat Commun. 2021 Nov 22;12(1):6784. doi: 10.1038/s41467-021-26660-7.
The control of the in-plane domain evolution in ferroelectric thin films is not only critical to understanding ferroelectric phenomena but also to enabling functional device fabrication. However, in-plane polarized ferroelectric thin films typically exhibit complicated multi-domain states, not desirable for optoelectronic device performance. Here we report a strategy combining interfacial symmetry engineering and anisotropic strain to design single-domain, in-plane polarized ferroelectric BaTiO thin films. Theoretical calculations predict the key role of the BaTiO/PrScO [Formula: see text] substrate interfacial environment, where anisotropic strain, monoclinic distortions, and interfacial electrostatic potential stabilize a single-variant spontaneous polarization. A combination of scanning transmission electron microscopy, piezoresponse force microscopy, ferroelectric hysteresis loop measurements, and second harmonic generation measurements directly reveals the stabilization of the in-plane quasi-single-domain polarization state. This work offers design principles for engineering in-plane domains of ferroelectric oxide thin films, which is a prerequisite for high performance optoelectronic devices.
铁电薄膜面内畴演化的控制不仅对于理解铁电现象至关重要，而且对于实现功能器件制造也至关重要。然而，面内极化铁电薄膜通常表现出复杂的多畴状态，这对于光电器件性能而言并非理想状态。在此，我们报道了一种结合界面对称性工程和各向异性应变的策略，以设计单畴、面内极化的铁电钛酸钡薄膜。理论计算预测了钛酸钡/钪酸镨衬底界面环境的关键作用，其中各向异性应变、单斜畸变和界面静电势稳定了单变体自发极化。扫描透射电子显微镜、压电力显微镜、铁电滞回环测量和二次谐波产生测量相结合，直接揭示了面内准单畴极化状态的稳定性。这项工作为铁电氧化物薄膜面内畴的工程设计提供了原理，这是高性能光电器件的先决条件。
