Ferrotoroidic polarons in antiferrodistortive SrTi O 3

Discovery of new quasiparticles with nontrivial topological field textures, such as polar vortices, skyrmions, and merons, holds promise in technological paradigms. Here, the authors demonstrate a ferroelectric quasiparticle with topological polarization vortices by engineering excess electron polarons. They further show that the electron polaron carries a magnetic moment coupled with ferrotoroidicity, i.e., the magnetoelectric effect. This result provides insight into the ultimate miniaturization of ferrotoroic materials and a new class of functional polaron families.