Spin dynamics and relaxation in the classical-spin Kondo-impurity model beyond the Landau-Lifschitz-Gilbert equation

Abstract

The real-time dynamics of a classical spin in an external magnetic field and locally exchange coupled to an extended one-dimensional system of non-interacting conduction electrons is studied numerically. Retardation effects in the coupled electron-spin dynamics are shown to be the source for the relaxation of the spin in the magnetic field. Total energy and spin is conserved in the non-adiabatic process. Approaching the new local ground state is therefore accompanied by the emission of dispersive wave packets of excitations carrying energy and spin and propagating through the lattice with Fermi velocity. While the spin dynamics in the regime of strong exchange coupling J is rather complex and governed by an emergent new time scale, the motion of the spin for weak J is regular and qualitatively well described by the Landau-Lifschitz-Gilbert (LLG) equation. Quantitatively, however, the full quantum-classical hybrid dynamics differs from the LLG approach. This is understood as a breakdown of weak-coupling perturbation theory in J in the course of time. Furthermore, it is shown that the concept of the Gilbert damping parameter is ill-defined for the case of a one-dimensional system.

15 pages, 13 figures, v2 with minor changes

References in corpus (10)

• Lieb-Robinson bounds and the generation of correlations and topological quantum order
• Microscopic approach to current-driven domain wall dynamics
• Observation of two-orbital spin-exchange interactions with ultracold SU(N)-symmetric fermions
• Direct observation of coherent inter-orbital spin-exchange dynamics
• Consistent classical and quantum mixed dynamics
• The emergence of classical behavior in magnetic adatoms
• Non-equilibrium cluster-perturbation theory
• Detection of spin reversal and nutations through current measurements
• Entanglement dynamics in a quantum-classical hybrid of two q-bits and one oscillator
• Spin dynamics of Mn impurities and their bound acceptors in GaAs

Cited by in corpus (33)

• Time-retarded damping and magnetic inertia in the Landau-Lifshitz-Gilbert equation self-consistently coupled to electronic time-dependent nonequilibrium Green functions
• Spin and charge pumping by steady or pulse current-driven magnetic domain wall: A self-consistent multiscale time-dependent-quantum/time-dependent-classical approach
• Spin dynamics of itinerant electrons: local magnetic moment formation and Berry phase
• Characteristic Timescales of the Local Moment Dynamics in Hund's-metals
• Spintronics meets nonadiabatic molecular dynamics: Geometric spin torque and damping on noncollinear classical magnetism due to electronic open quantum system
• Anomalous spin precession under a geometrical torque
• Relaxation of a classical spin coupled to a strongly correlated electron system
• Magnon versus electron mediated spin-transfer torque exerted by spin currents across antiferromagnetic insulator to switch magnetization of adjacent ferromagnetic metal
• Magnon-driven chiral charge and spin pumping and electron-magnon scattering from time-dependent quantum transport combined with atomistic spin dynamics theory
• Inertia effects in the real-time dynamics of a quantum spin coupled to a Fermi sea
• Annihilation of topological solitons in magnetism with spin wave burst finale: The role of nonequilibrium electrons causing nonlocal damping and spin pumping over ultrabroadband frequency range
• Gilbert damping in metallic ferromagnets from Schwinger-Keldysh field theory: Intrinsically nonlocal and nonuniform, and made anisotropic by spin-orbit coupling
• Topological spin torque emerging in classical-spin systems with different time scales
• 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
• Bath-induced spin inertia
• Long-time relaxation dynamics of a spin coupled to a Chern insulator
• Unified framework of the microscopic Landau-Lifshitz-Gilbert equation and its application to Skyrmion dynamics
• Emergent Non-Abelian Gauge Theory in Coupled Spin-Electron Dynamics
• Spin Berry curvature of the Haldane model
• Versatile Approach to the Spin Dynamics in Correlated Electron Systems
• Anisotropic skyrmion mass induced by surrounding conduction electrons: A Schwinger-Keldysh field theory approach
• Dynamics of spin relaxation in nonequilibrium magnetic nanojunctions
• Nonlocal damping of spin waves in a magnetic insulator induced by normal, heavy, or altermagnetic metallic overlayer: A Schwinger-Keldysh field theory approach
• Nonequilibrium dynamics in a spin valve with noncollinear magnetization
• Controlling the real-time dynamics of a spin coupled to the helical edge states of the Kane-Mele model
• Non-Hamiltonian dynamics of indirectly coupled classical impurity spins
• Landau-Lifshitz damping from Lindbladian dissipation in quantum magnets
• Microscopic theory of spin friction and dissipative spin dynamics
• Prerelaxation in quantum, classical, and quantum-classical two-impurity models
• Geometrical torque on magnetic moments coupled to a correlated antiferromagnet
• Relaxation dynamics of a quantum spin coupled to a topological edge state
• Optically induced magnetic inertia and magnons from non-Markovian extension of the Landau-Lifshitz-Gilbert equation