Stacking dependent ferroelectricity and antiferroelectricity in quasi-one-dimensional oxyhalides NbOX3

Low-dimensional ferroelectricity and polar materials have attracted considerable attention 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 NbOX3 (X = Cl, Br, and 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 the 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 BaTiO3 and piezoelectric ZnO, respectively. Our paper demonstrates that the van der Waals NbOX3 are promising materials for exploring quasi-one-dimensional ferroelectricity and antiferroelectricity.