Spin effects in electron vortex states

TL;DR

This paper investigates the relativistic spin effects in electron vortex beams, highlighting how spin coupling influences vortex states and their creation in electron microscopes, with implications for advanced electron beam manipulation.

Contribution

It explores the role of spin and total angular momentum in electron vortex beams, revealing relativistic effects and proposing methods for their experimental realization.

Findings

Spin effects vanish in the paraxial limit.

Relativistic spin coupling influences vortex states.

Magnetic apertures are needed to exploit spin effects.

Abstract

The recent experimental realization of electron vortex beams opens up a wide research domain previously unexplored. The present paper explores the relativistic properties of these electron vortex beams, and quantifies deviations from scalar wave theory. It is common in electron optics to use the Schr\"odinger equation neglecting spin. The present paper investigates the role of spin and the total angular momentum Jz and how it pertains to the vortex states. As an application, we also investigate if it is possible to use holographic reconstruction to create novel total angular momentum eigenstates in a Transmission Electron Microscope. It is demonstrated that relativistic spin coupling effects disappear in the paraxial limit, and spin effects in holographically created electron vortex beams can only be exploited by using specialized magnetic apertures.