Waves of spin-current in magnetized dielectrics

TL;DR

This paper derives quantum hydrodynamics equations including a spin-current evolution equation and demonstrates the emergence of new collective excitations called spin-current waves in magnetized dielectrics.

Contribution

It introduces a set of QHD equations with a novel spin-current evolution equation derived from microscopic principles.

Findings

Discovery of spin-current waves as new collective excitations.

Derivation of QHD equations from the many-particle Schrödinger equation.

Analysis of dispersion relations in magnetized dielectric samples.

Abstract

Spin-current is an important physical quantity in present day spintronics and it might be very usefull in the physics of quantum plasma of spinning particles. Thus it is important to have an equation of the spin-current evolution. This equation naturally appears as a part of a set of the quantum hydrodynamics (QHD) equations. Consequently, we present the set of the QHD equations derived from the many-particle microscopic Schrodinger equation, which consists of the continuity equation, the Euler equation, the Bloch equation and equation of the spin-current evolution. We use these equations to study dispersion of the collective excitations in the three dimensional samples of the magnetized dielectrics. We show that dynamics of the spin-current leads to formation of new type of the collective excitations in the magnetized dielectrics, which we called spin-current waves.