Steering Magnetic Skyrmions with Nonequilibrium Green's Functions

Abstract

Magnetic skyrmions, topologically protected vortex-like configurations in spin textures, are of wide conceptual and practical appeal for quantum information technologies, notably in relation to the making of so-called race-track memory devices. Skyrmions can be created, steered and destroyed with magnetic fields and/or (spin) currents. Here we focus on the latter mechanism, analyzed via a microscopic treatment of the skyrmion-current interaction. The system we consider is an isolated skyrmion in a square-lattice cluster, interacting with electrons spins in a current-carrying quantum wire. For the theoretical description, we employ a quantum formulation of spin-dependent currents via nonequilibrium Green's functions (NEGF) within the generalized Kadanoff-Baym ansatz (GKBA). This is combined with a treatment of skyrmions based on classical localized spins, with the skyrmion motion described via Ehrenfest dynamics. With our mixed quantum-classical scheme, we assess how time-dependent currents can affect the skyrmion dynamics, and how this in turn depends on electron-electron and spin-orbit interactions in the wire. Our study shows the usefulness of a quantum-classical treatment of skyrmion steering via currents, as a way for example to validate/extract an effective, classical-only, description of skyrmion dynamics from a microscopic quantum modeling of the skyrmion-current interaction.

arXiv comment10 pages, 8 figures, contribution to the proceedings of "Progress in Nonequilibrium Green's Functions VII"

References in corpus (33)

• Skyrmion Lattice in a Chiral Magnet
• Spontaneous Skyrmion Ground States in Magnetic Metals
• Observation of room temperature magnetic skyrmions and their current-driven dynamics in ultrathin Co films
• Interface-Induced Phenomena in Magnetism
• Theory of current-driven motion of Skyrmions and spirals in helical magnets
• Static and Dynamical Properties of Antiferromagnetic Skyrmions in the Presence of Applied Current and Temperature
• Skyrmions and Anomalous Hall Effect in a Dzyloshinskii-Moriya Spiral Magnet
• Electric field driven switching of individual magnetic skyrmions
• Ginzburg-Landau theory for skyrmions in inversion-symmetric magnets with competing interactions
• Conserving approximations in time-dependent quantum transport: Initial correlations and memory effects
• Three-sublattice Skyrmion crystal in the antiferromagnetic triangular lattice
• Numerical simulations of time resolved quantum electronics
• Successes and Failures of Kadanoff-Baym Dynamics in Hubbard Nanoclusters
• Dynamics of the antiferromagnetic skyrmion induced by a magnetic anisotropy gradient
• Charge dynamics in molecular junctions: Nonequilibrium Green's Function approach made fast
• Phase diagram of the classical Heisenberg antiferromagnet on a triangular lattice in applied magnetic field
• Theory of Topological Spin Hall Effect in Antiferromagnetic Skyrmion: Impact on Current-induced Motion
• Ab initio transport results for strongly correlated fermions
• Spin and charge pumping by steady or pulse current-driven magnetic domain wall: A self-consistent multiscale time-dependent-quantum/time-dependent-classical approach
• Charge separation in donor-C60 complexes with real-time Green's functions: The importance of nonlocal correlations
• Non-equilibrium Green's function approach to inhomogeneous quantum many-body systems using the Generalized Kadanoff Baym Ansatz
• Stopping dynamics of ions passing through correlated honeycomb clusters
• CHEERS: A tool for Correlated Hole-Electron Evolution from Real-time Simulations
• Multiscale simulations of topological transformations in magnetic Skyrmions
• Molecular junctions and molecular motors: Including Coulomb repulsion in electronic friction using nonequilibrium Green's functions
• Anomalous spin precession under a geometrical torque
• How to construct the proper gauge-invariant density matrix in steady-state nonequilibrium: Applications to spin-transfer and spin-orbit torques
• The generalized Kadanoff-Baym ansatz. Computing nonlinear response properties of finite systems
• Merging Features from Green's Functions and Time Dependent Density Functional Theory: A Route to the Description of Correlated Materials out of Equilibrium?
• Disorder and interactions in systems out of equilibrium: The exact independent-particle picture from density functional theory
• Can we always get the entanglement entropy from the Kadanoff-Baym equations? The case of the T-matrix approximation
• Semi-Classical Dynamics in Quantum Spin Systems
• Nonequilibrium Green's functions and atom-surface dynamics: Simple views from a simple model system

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• Quantum many-body states and Green functions of nonequilibrium electron-magnon systems: Localized spin operators vs. their mapping to Holstein-Primakoff bosons
• 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
• 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
• Löwdin's symmetry dilemma within Green functions theory for the one-dimensional Hubbard model
• Anisotropic skyrmion mass induced by surrounding conduction electrons: A Schwinger-Keldysh field theory approach
• Dynamics of spin relaxation in nonequilibrium magnetic nanojunctions
• Nonequilibrium dynamics in a spin valve with noncollinear magnetization
• Interacting electrons in a flat-band system within the Generalized Kadanoff-Baym Ansatz
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