Novel Ferroelectric Properties Induced by Low-Dimensional Nano-Structures and Its Mechanical Control

在这项研究中，通过大规模的量子力学模拟和并行计算，分析了低维纳米结构中的新型铁电性质。在纳米薄膜、纳米线、纳米管和纳米点等所有纳米结构中都成功地观察到了一种与体相对应的结构完全不同的涡旋状极化结构。研究发现，这些特性强烈地依赖于部件的形状。此外，还分析了这种新型铁电性质与机械应变之间的耦合，即多物理性质。结果表明，极化涡旋的存在、强度和数目随着应变的变化而变化。这表明低维铁电纳米结构具有显著的多物理特性。

In this study, novel ferroelectric properties in low-dimensional nanostructures are analyzed by large-scale quantum-mechanics simulations using parallel computations. A novel vortex-like polarization structure, which is totally different from that of the bulk counterpart, is successfully observed in all nanostructures such as nano-films, nanowires, nanotubes, and nanodots. The properties are found to be strongly dependent on the shape of components. Furthermore, the coupling between this novel ferroelectric properties and mechanica strain, i.e., multi-physics properties, is analyzed. It is revealed that the presence, strength, and numbers of polarization vortices change with respect to the strain. This indicates that there exist remarkable multi-physics properties in low-dimensional ferroelectric nanostructures.