Spin Magnetic Moment and Persistent Orbital Currents in Cylindrical Nanolayer

TL;DR

This paper derives analytical expressions for persistent orbital and spin magnetic moment currents in a cylindrical nanolayer under an axial magnetic field, revealing how geometry influences current behavior and conditions for spin-only currents.

Contribution

It provides new analytical formulas for current densities in cylindrical nanolayers and identifies conditions for spin magnetic moment currents without orbital contributions.

Findings

Spin magnetic moment current can be isolated in certain conditions.

The radial dependence of spin current is non-monotonic in layered geometries.

Orbital current can vanish at specific radial coordinates depending on field and electron rotation.

Abstract

Densities of persistent orbital and spin magnetic moment currents of an electron in a cylindrical nanolayer in the presence of external axial magnetic field are considered. For the mentioned current densities analytical expressions are obtained. The conditions when in the system only spin magnetic moment current is present are defined. Dependencies of orbital and spin magnetic moment currents on geometrical parameters of nanolayer are derived. It is shown that in the case of layered geometry the dependence of spin magnetic moment current on radial coordinate has a non-monotonic behavior. This is the peculiarity of layered geometry of nanostructure and it is due to the behavior of wave function of the system along the radial direction. Dependent on the directions of the field and orbital rotation of the electron there are defined values of radial coordinates when the orbital current disappears. The transition to the case of cylindrical quantum dot is discussed as well.