Low-dimensional ferroelectricity and polar materials have attracted considerable attentions for their fascinating physics and potential applications. Based on first-principles calculations, here we investigate the stacking modes and polar properties of a typical series of quasi-one-dimensional ferroelectrics: double-chain oxyhalides NbO$X_3$ ($X$=Cl, Br, I). The geometry of their double-chains allows both the interchain/intrachain permutation. Thus, different stacking modes of double-chains lead to a variety of ferroelectric and antiferroelectric phases in both the tetragonal and monoclinic crystals. The proximate energies of these phases may lead to multiphase coexistence in real materials, as well as the hydrostatic pressure driving structural phase transition. Their spontaneous polarizations and piezoelectricity of the ferroelectric phases are prominent, comparable to commercially used ferroelectric BaTiO$_3$ and piezoelectric ZnO, respectively. Our work demonstrates that the van der Waals NbO$X_3$ are promising materials for exploring quasi-one-dimensional ferroelectricity and antiferroelectricity.

中文翻译：

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准一维卤氧化物中的堆叠依赖铁电性和反铁电性 NbO$X_3$

低维铁电体和极性材料因其迷人的物理特性和潜在应用而备受关注。基于第一性原理计算，我们在此研究了一系列典型的准一维铁电体的堆叠模式和极性特性：双链卤氧化物 NbO$X_3$ ($X$=Cl, Br, I)。它们双链的几何形状允许链间/链内排列。因此，双链的不同堆叠模式导致四方晶体和单斜晶体中存在多种铁电和反铁电相。这些相的近似能量可能导致真实材料中的多相共存，以及驱动结构相变的静水压力。它们的自发极化和铁电相的压电性非常突出，分别可与商业使用的铁电 BaTiO$_3$ 和压电 ZnO 相媲美。我们的工作表明，范德华 NbO$X_3$ 是探索准一维铁电体和反铁电体的有前途的材料。