Electron vortex beams in a magnetic field and spin filter

TL;DR

This paper studies how electron vortex beams behave in magnetic fields, revealing modifications in Berry curvature and spin-orbit interactions, leading to spin Hall effects and spin filtering phenomena.

Contribution

It introduces the impact of magnetic fields on electron vortex beams, showing how Berry curvature and spin interactions are altered, resulting in novel spin filtering effects.

Findings

Magnetic fields modify Berry curvature for electron vortex beams.

Tilted vortex beams induce spin Hall effects in free space.

Magnetic fields enable spin filtering with spin clustering.

Abstract

We investigate the propagation of electron vortex beams in a magnetic field. It is pointed out that when electron vortex beams carrying orbital angular momentum propagate in a magnetic field, the Berry curvature associated with the scalar electron moving in a cyclic path around the vortex line is modified from that in free space. This alters the spin-orbit interaction, which affects the propagation of nonparaxial beams. The electron vortex beams with tilted vortex lead to spin Hall effect in free space. In presence of a magnetic field in time space we have spin filtering such that either positive or negative spin states emerge in spin Hall currents with clustering of spin $\frac{1}{2}$ states.