Nonequilibrium Spin Magnetization Quantum Transport Equations: Spin and Charge Coupling

TL;DR

This paper extends classical spin magnetization transport equations to a fully quantum, nonlinear, and time-dependent framework, incorporating spin-orbit coupling and many-body effects for advanced spintronic applications.

Contribution

It introduces the SMQDFT equations that couple charge and spin magnetization distributions, capturing quantum many-body effects absent in classical models.

Findings

Derivation of fully time-dependent spin magnetization quantum transport equations.

Inclusion of spin-orbit coupling and spin-dependent scattering effects.

Framework for computational modeling of spintronic and nanomagnetic devices.

Abstract

The classical Bloch equations of spin magnetization transport is extended to fully time-dependent and highly-nonlinear nonequilibrium spin magnetization quantum distribution function transport (SMQDFT) equations. The relevant variables are the spinor correlation functions which separate into charge and spin magnetization distributions that becomes highly coupled in SMQDFT equa- tions. The leading terms consist of the Boltzmann kinetic equation with spin-orbit coupling in a magnetic eld together with spin-dependent scattering terms which contribute to the torque. These do not have analogue within the classical relaxation-dephasing picture, but are inherently quantum many-body effects. These should incorporate the spatiotemporal-dependent phase-space dynam- ics of Elliot-Yafet and Dyakonov-Perel scatterings. The resulting SMQDFT equations should serve as a theoretical foundation for computational spintronic and nanomagnetic device applications, in ultrafast-switching-speed/low-power performance and reliability analyses.