Effect of electrical boundary conditions on the domain stability of porous ferroelectric nanowires

The electrical boundary condition plays an important role in the manipulation of domain structures in low-dimensional ferroelectric materials, especially ferroelectric nanowires. Here, using phase-field simulations, we systematically investigate the influence of electrical boundary conditions on the domain structure in porous PbTiO₃ ferroelectric nanowires. Our results demonstrate the formation of four types of domain structures via varying electrical boundary conditions, which possess distinguished local polarization and energy configurations. We further show that the domain structures are also dependent on the nanowire radius, including the breakdown of a metastable concentric toroidal domain structure upon reducing the radius to 14 nm. The present work provides guidance for further experimental studies on the control of polar domain structures through manipulating the electrical boundary condition and the ferroelectric size, which paves the way for developing multi-functions of low-dimensional ferroelectric systems.