论文标题
使用电子涡流束检测磁杂质
Detection of magnetic impurities using electron vortex beams
论文作者
论文摘要
电子显微镜脱颖而出，因为电子波与光学对应物相比提供了更高的空间分辨能力。在这里，我们从理论上研究了在透射电子显微镜（TEM）和磁杂质中产生的扭曲电子的相互作用，其中将磁偶极矩作为演示元件。除了通常的光相外，磁偶极矩产生的不均匀矢量电势还为电子的固有轨道角动量做出了额外的贡献，从而导致了gouy相移。通过干扰传出的扭曲电子束与参考高斯圆柱形波，可以通过旋转和变形的干扰模式直接确定磁偶极子的大小和方向。获得的结果证明了扭曲的电子束对TEM探测杂质的原子和纳米级磁性的有用性，而建议的模型为TEM方法的未来发展提供了概念基础。
Electron microscopy stands out as electron waves providing higher spatial resolving power compared to their optical counterpart. Here we investigate theoretically the interaction of twisted electrons generated in transmission electron microscope (TEM) and magnetic impurity, in which the magnetic dipole moment is taken as a demonstration element. In addition to the usual optical phase, the inhomogeneous vector potential generated by the magnetic dipole moment makes additional contribution to the intrinsic orbital angular momentum of electrons, resulting in a Gouy phase shift. By interfering the outgoing twisted electron beam with a reference Gaussian-cylindrical wave, one can determine the magnitude and orientation of magnetic dipole directly via the rotational and deformed interference pattern. The obtained results demonstrate the usefulness of twisted electron beams for probing the atomic- and nanoscale magnetism of impurity by TEM and the proposed model provides the conceptual basis for future developments of the TEM method.
