World Premier International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS) , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
J Am Chem Soc. 2017 Aug 9;139(31):10868-10874. doi: 10.1021/jacs.7b05665. Epub 2017 Jul 27.
Complex perovskite oxides offer tremendous potential for controlling their rich variety of electronic properties, including high-T superconductivity, high-κ ferroelectricity, and quantum magnetism. Atomic-scale control of these intriguing properties in ultrathin perovskites is an important challenge for exploring new physics and device functionality at atomic dimensions. Here, we demonstrate atomic-scale engineering of dielectric responses using two-dimensional (2D) homologous perovskite nanosheets (CaNaNbO; m = 3-6). In this homologous 2D material, the thickness of the perovskite layers can be incrementally controlled by changing m, and such atomic layer engineering enhances the high-κ dielectric response and local ferroelectric instability. The end member (m = 6) attains a high dielectric constant of ∼470, which is the highest among all known dielectrics in the ultrathin region (<10 nm). These results provide a new strategy for achieving high-κ ferroelectrics for use in ultrascaled high-density capacitors and post-graphene technology.
复杂钙钛矿氧化物在控制其丰富多样的电子特性方面具有巨大的潜力，包括高温超导性、高介电常数铁电性和量子磁性。在超薄钙钛矿中对这些有趣特性进行原子级控制是探索新物理和原子尺度器件功能的重要挑战。在这里，我们使用二维（2D）同系物钙钛矿纳米片（CaNaNbO；m=3-6）展示了介电响应的原子级工程。在这种同系 2D 材料中，通过改变 m 可以逐步控制钙钛矿层的厚度，这种原子层工程增强了高介电常数的介电响应和局部铁电不稳定性。端基元（m=6）获得了约 470 的高介电常数，这在所有已知的超薄区（<10nm）介电材料中是最高的。这些结果为实现用于超小型高密度电容器和后石墨烯技术的高介电常数铁电体提供了一种新策略。
