Anisotropic skyrmion mass induced by surrounding conduction electrons: A Schwinger-Keldysh field theory approach

Abstract

The current-driven motion of magnetic skyrmions, as topologically protected winding vector fields of local magnetization, has attracted considerable attention due to both fundamental interest in the dynamics of topological solitons, and potential spintronic applications. While widely-used Thiele equation with zero skyrmion mass captures its rigid motion under the assumption of preserved skyrmion shape, experiments on realistic skyrmions find deviation due to inertial mass with numerous attempts to account for it by invoking internal skyrmion dynamics, geometry of the nanowire, and interaction with magnons or phonons. However, experimentally observed skyrmion mass is often much larger than predicted by these theories. In this Letter, we employ Schwinger-Keldysh field-theoretical approach to study conduction electrons interacting with localized magnetic moments comprising a skyrmion to obtain a stochastic differential equation of its motion. By analyzing its time-retarded damping kernel, we extract an anisotropic mass governed by conduction electrons and demonstrate its substantial effect on the current-driven skyrmion motion, even in the absence of any skyrmion deformation.

References in corpus (36)

• Spin Transfer Torques
• Room temperature chiral magnetic skyrmion in ultrathin magnetic nanostructures
• Beyond skyrmions: Review and perspectives of alternative magnetic quasiparticles
• Field-Dependent Size and Shape of Single Magnetic Skyrmions
• Inertia and chiral edge modes of a skyrmion magnetic bubble
• Skyrmion Qubits: A New Class of Quantum Logic Elements Based on Nanoscale Magnetization
• Néel-type skyrmions and their current-induced motion in van der Waals ferromagnet-based heterostructures
• Inertia, diffusion and dynamics of a driven skyrmion
• Memory functions of magnetic skyrmions
• Skyrmion dynamics in chiral ferromagnets
• Brownian reservoir computing realized using geometrically confined skyrmions
• Schwinger-Keldysh formalism I: BRST symmetries and superspace
• The Magnus Force on Skyrmions in Ferromagnets and the Quantum Hall Effect
• Computing and Memory Technologies based on Magnetic Skyrmions
• Effective gauge field theory of spintronics
• Skyrmions Driven by Intrinsic Magnons
• Schwinger-Keldysh formalism II: Thermal equivariant cohomology
• 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
• Skyrmions in twisted bilayer graphene: stability, pairing, and crystallization
• Stochastic Langevin equations: Markovian and non-Markovian dynamics
• Spin dynamics and relaxation in the classical-spin Kondo-impurity model beyond the Landau-Lifschitz-Gilbert equation
• Effective temperature and Gilbert damping of a current-driven localized spin
• 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
• Atomistic perspective of long lifetimes of small skyrmions at room temperature
• A micromagnetic theory of skyrmion lifetime in ultrathin ferromagnetic films
• Steering Magnetic Skyrmions with Nonequilibrium Green's Functions
• Dynamics of topological solitons in two-dimensional ferromagnets
• Skyrmion Mass from Spin-Phonon Interaction
• How a skyrmion can appear both massive and massless
• Gilbert damping in metallic ferromagnets from Schwinger-Keldysh field theory: Intrinsically nonlocal and nonuniform, and made anisotropic by spin-orbit coupling
• 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
• Field-driven skyrmion motion through velocity equipartition between skyrmions and a domain wall
• Electron Induced Massive Dynamics of Magnetic Domain Walls
• Curvature-Induced Skyrmion Mass

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• Quantum Magnetic Skyrmions on Kondo-type Lattices
• Controllable and Non-Dissipative Inertial Dynamics of Skyrmion in a Bosonic Platform
• Optically induced magnetic inertia and magnons from non-Markovian extension of the Landau-Lifshitz-Gilbert equation