Ye Mao, Hu Songbai, Zhu Yuanmin, Zhang Yubo, Ke Shanming, Xie Lin, Zhang Yuan, Hu Sixia, Zhang Dongwen, Luo Zhenlin, Gu Meng, He Jiaqing, Zhang Peihong, Zhang Wenqing, Chen Lang
Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China.
Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen 518055, China.
Nano Lett. 2021 Jan 13;21(1):144-150. doi: 10.1021/acs.nanolett.0c03417. Epub 2020 Dec 11.
Materials with reduced dimensions have been shown to host a wide variety of exotic properties and novel quantum states that often defy textbook wisdom. Polarization switching and metallic screening are well-known examples of mutually exclusive properties that cannot coexist in bulk solids. Here we report the fabrication of (SrRuO)/(BaTiO) superlattices that exhibits reversible polarization switching in an atomically thin metallic layer. A multipronged investigation combining structural analyses, electrical measurements, and first-principles electronic structure calculations unravels the coexistence of two-dimensional (2D) metallicity in the SrRuO layer accompanied by the breaking of inversion symmetry, supporting electric polarization along the out-of-plane direction. Such a 2D ferroelectric-like metal paves a novel way to engineer a quantum multistate with unusual coexisting properties, such as ferroelectrics and metals, manipulated by external fields.
尺寸减小的材料已被证明具有多种奇异特性和新颖的量子态，这些特性常常违背传统教科书知识。极化切换和金属屏蔽是众所周知的相互排斥的特性示例，它们在块状固体中无法共存。在此，我们报告了(SrRuO)/(BaTiO)超晶格的制备，该超晶格在原子级薄的金属层中表现出可逆的极化切换。结合结构分析、电学测量和第一性原理电子结构计算的多方面研究揭示了SrRuO层中二维（2D）金属性与反演对称性破缺的共存，支持沿面外方向的电极化。这种二维类铁电金属为设计一种由外部场操控的具有铁电体和金属等异常共存特性的量子多态开辟了一条新途径。
