The polarization-modulated electronic structure and giant tunneling-electroresistance effect of a one-dimensional ferroelectric Ta4OTe9I4 nanowire

Low-dimensional ferroelectrics have a great deal of potential for use in electronic memory devices. However, intrinsic one-dimensional (1D) ferroelectricity is very rare. Using first-principles calculations, we present the discovery of an inborn 1D Ta4OTe9I4 ferroelectric (FE) nanowire. Its distinctive geometry can cause spontaneous electric polarization along the z-axis and allow it to maintain a certain temperature and strain. In addition to its sizable spontaneous polarization and appropriate Curie temperature, the 1D Ta4OTe9I4 nanowire exhibits an energy barrier comparable to those of other ferroelectrics. With polarization reversal, the energy gap can be modulated in the range of 0.38–1.33 eV, corresponding to an apparent peak shift phenomenon in the optical response. We use this nanowire as an exemplary material for building a FE tunnel junction composed of Hf0.5Ta3.5OTe9I4/Ta4OTe9I4/W0.5Ta3.5OTe9I4 with a giant tunneling electroresistance ratio at zero and low bias. Our calculations suggest that this 1D intrinsically FE material obtained from van der Waals crystals can be used in miniaturized and advanced high-density information storage.