论文标题
将轨道角动量转移到电子束上，揭示了环形和手性秩
Transferring Orbital Angular Momentum to an Electron Beam Reveals Toroidal and Chiral Order
论文作者
论文摘要
轨道角动量和扭矩传递在各种磁质地和设备中扮演着核心角色，包括天空和旋转刺激电子设备（1-4）。现在，在铁电特性中也探索了类似的拓扑结构，包括铁电/介电超晶格中的极化涡流阵列（5）。与磁环形阶不同，电动环序不会直接与线性外部磁场。为了开发一种可以控制极化涡流中开关的机制，我们利用了高能电子束，并表明横向电流是在弹道极限内通过极性产生的。我们发现，在铁旋转相中存在电动动力矩，可将可测量的扭矩和轨道角动量转移到电子束。此外，我们发现在这些异质结构中观察到的复杂极化模式在显微镜上是偏振的非平凡轴向成分的微观手性。这种手性为铁电和光学特性的耦合打开了门。
Orbital angular momentum and torque transfer play central roles in a wide range of magnetic textures and devices including skyrmions and spin-torque electronics(1-4). Analogous topological structures are now also being explored in ferroelectrics, including polarization vortex arrays in ferroelectric/dielectric superlattices(5). Unlike magnetic toroidal order, electric toroidal order does not couple directly to linear external fields. To develop a mechanism that can control switching in polarization vortices, we utilize a high-energy electron beam and show that transverse currents are generated by polar order in the ballistic limit. We find that the presence of an electric toroidal moment in a ferro-rotational phase transfers a measurable torque and orbital angular momentum to the electron beam. Furthermore, we find that the complex polarization patterns, observed in these heterostructures, are microscopically chiral with a non-trivial axial component of the polarization. This chirality opens the door for the coupling of ferroelectric and optical properties.
