Quasi‐1D Antiferroelectricity in Centrosymmetric CsTaS₃ Crystal

Abstract

1D ferroelectric (FE) materials are expected to be promising low-dimensional materials for nanometer devices, but are rarely reported. The previous experiment discovered that quasi-1D CsTaS 3 crystalizes in centrosymmetric space group, but in which the Ta cations have a strange shift along the c axis from the center of TaS 6 octahedron. Here, the crystal structure, electronic structure, ferroelectric, and piezoelectric properties of CsTaS 3 by using first-principles calculations are studied. It is found that the empty d orbitals of Ta cations induce the distortions of TaS 6 octahedra, which bring the polarity along a given [TaS 3 ] − chain. The adjacent chains are antiferroelectric (AFE) coupling making CsTaS 3 being an AFE material. However, the FE phase of CsTaS 3 is supposed to be accessible since its total energy is only 0.3 meV per formula higher than that of the AFE phase. The polarization of FE CsTaS 3 is estimated to be 16.8 𝝁C cm −2 , which is comparable to those of well-known FE perovskites. The work predicts a quasi-1D AFE material, which would be helpful for subsequent experimental work.