Intrinsic ferroelectrics and carrier doping-induced metallic multiferroics in an atomic wire

Low-dimensional multiferroic metals characterized by the simultaneous coexistence of ferroelectricity, conductivity, and magnetism hold tremendous potential for scientific and technological endeavors. However, the mutually exclusive mechanisms among these properties impede the discovery of multifunctional conducting multiferroics, especially at the atomic-scale. Here, based on first-principles calculations, we design and demonstrate intrinsic one-dimensional (1D) ferroelectrics and carrier doping-induced metallic multiferroics in an atomic WOF4 wire. The WOF4 atomic wire that can be derived from a 1D van der Waals crystal exhibits pronounced ferroelectricity manifested in the form of large cooperative atomic displacements. By performing Monte Carlo simulations with an effective Hamiltonian method, we obtain the nanowire that can sustain a high Curie temperature, indicating its potential for room-temperature applications. Moreover, doping with electrons is found to induce magnetism and metallic conductivity that coexists with the ferroelectric distortion in the nanowire. These appealing properties in conjunction with the experimental feasibility enable the doped WOF4 nanowire to act as a promising atomic-scale multifunctional material.