Dynamics of spin relaxation in nonequilibrium magnetic nanojunctions

Abstract

We investigate nonequilibrium phenomena in magnetic nano-junctions using a numerical approach that combines classical spin dynamics with the hierarchical equations of motion technique for quantum dynamics of conduction electrons. Our focus lies on the spin dynamics, where we observe non-monotonic behavior in the spin relaxation rates as a function of the coupling strength between the localized spin and conduction electrons. Notably, we identify a distinct maximum at intermediate coupling strength, which we attribute to a competition that involves the increasing influence of the coupling between the classical spin and electrons, as well as the influence of decreasing local density of states at the Fermi level. Furthermore, we demonstrate that the spin dynamics of a large open system can be accurately simulated by a short chain coupled to semi-infinite metallic leads. In the case of a magnetic junction subjected to an external DC voltage, we observe resonant features in the spin relaxation, reflecting the electronic spectrum of the system. The precession of classical spin gives rise to additional side energies in the electronic spectrum, which in turn leads to a broadened range of enhanced damping in the voltage.

27 pages, 11 figures

References in corpus (23)

• Spin Transfer Torques
• Perspective: Numerically "exact" approach to open quantum dynamics: The hierarchical equations of motion (HEOM)
• Microscopic approach to current-driven domain wall dynamics
• Interface enhancement of Gilbert damping from first-principles
• Spirit: Multifunctional Framework for Atomistic Spin Simulations
• Time-dependent density-functional theory for open systems
• Two-color spin noise spectroscopy: Using spin fluctuation correlations to reveal homogeneous linewidths within quantum dot ensembles
• Relativistic theory of spin relaxation mechanisms in the Landau-Lifshitz-Gilbert equation of spin dynamics
• Spin noise spectroscopy beyond thermal equilibrium and linear response
• Hierarchical quantum master equation approach to current fluctuations in nonequilibrium charge transport through nanosystems
• Effective temperature and Gilbert damping of a current-driven localized spin
• The emergence of classical behavior in magnetic adatoms
• Topical Review on Skyrmions and Hall Transport
• Subnanosecond switching of local spin-exchange coupled to ferromagnets
• Simulation of Charge Transport in Organic Semiconductors: A Time-Dependent Multiscale Method Based on Non-Equilibrium Green's Functions
• Inertia effects in the real-time dynamics of a quantum spin coupled to a Fermi sea
• An observable effect of spin inertia in slow magneto-dynamics: Increase of the switching error rates in nanoscale ferromagnets
• Spin dynamics at the singlet-triplet crossings in double quantum dot
• When can localized spins interacting with conduction electrons in ferro- or antiferromagnets be described classically via the Landau-Lifshitz equation: Transition from quantum many-body entangled to quantum-classical nonequilibrium states
• Accessing long timescales in the relaxation dynamics of spins coupled to a conduction-electron system using absorbing boundary conditions
• Subgap dynamics of double quantum dot coupled between superconducting and normal leads
• Long-time relaxation dynamics of a spin coupled to a Chern insulator
• Nonequilibrium dynamics in a spin valve with noncollinear magnetization

Cited by in corpus (4)

• Microscopic theory of spin friction and dissipative spin dynamics
• Scalable Effective Models for Superconducting Nanostructures: Applications to Double, Triple, and Quadruple Quantum Dots
• Spin transport through a nanojunction with a precessing anisotropic molecular spin: Quantum interference and spin-transfer torque
• Effect of uniaxial magnetic anisotropy on charge transport in a junction with a precessing anisotropic molecular spin