![]() ![]() Therefore, the dynamic property of isolated topological polar structures under external stimuli is little known and the ability to control individual topological polar structures that is critical for practical applications, e.g., data storage, for which one-by-one writing and erasing is required, is still challenging. Under external fields, they usually emerge and disappear simultaneously 22, 23, 24. For instance, one clockwise vortex is always sandwiched between two anticlockwise ones in a PbTiO 3 layer 7, and similar for flux-closure domains 6. However, in these studies, topological structures in the oxide superlattice always appear as arrays and thus the switching of them exhibits a collective behavior, usually involving multiple topological units. ![]() In such a similar system, vortex arrays switch to out-of-plane and in-plane polarization by electric fields and mechanical loading, respectively 23, 24. For example, in PbTiO 3/SrTiO 3 superlattices, reversible phase transition between flux-closure arrays and trivial ferroelectric phase driven by either electric or mechanical fields have been observed 22. To date, extensive theoretical and experimental studies have been carried out to explore the evolution of topological structures under electric and mechanical fields 18, 19, 20, 21. Practical applications of topological structures require the ability to manipulate them by using external stimuli and comprehensive understanding of their dynamic properties 13, 14, 15, 16, 17. These topological structures host unique properties that allow the development of novel electronics, including negative capacitance field-effect transistors 10, 11 and high-density non-volatile memories 12. For example, vertices (meeting points of two or more domain walls) 4, 5, 6, vortices (require a non-zero polarization curl) 7, polar skyrmions 8, and polar merons 9 have been synthesized in PbTiO 3 films, (PbTiO 3) n/(SrTiO 3) n superlattices or directly written in ferroelectrics by scanning probe techniques. ![]() This work demonstrates the ability to electrically manipulate isolated three-fold vertices, shedding light on the dynamic property of isolated topological polar structures.Ī variety of topological polar configurations have been created in complex oxides by precisely mediating the electrical and mechanical boundary conditions 1, 2, 3. Microstructural evolution of the nucleation and propagation of isolated three-fold vertices is further revealed by phase-field simulations. Utilizing the SrTiO 3 layer and in situ electrical testing system, we find that isolated three-fold vertices can move in a controllable and reversible manner with a velocity up to ~629 nm s −1. At the PbTiO 3/SrRuO 3 interface, a two-unit-cell thick SrTiO 3 layer provides electrical boundary conditions for the formation of three-fold vertices. ![]() Here, we show the controlled nucleation and motion of isolated three-fold vertices under an applied electric field. Despite the increasing evidence of their switchability under electrical and/or mechanical fields, the dynamic property of isolated ones, which is usually required for applications such as data storage, is still absent. Recently various topological polar structures have been discovered in oxide thin films. ![]()
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