Geometric Dynamics of Magnetization: Electronic Contribution

Abstract

To give a general description of the influences of electric fields or currents on magnetization dynamics, we developed a semiclassical theory for the magnetization implicitly coupled to electronic degrees of freedom. In the absence of electric fields the Bloch electron Hamiltonian changes the Berry curvature, the effective magnetic field, and the damping in the dynamical equation of the magnetization, which we classify into intrinsic and extrinsic effects. Static electric fields modify these as first-order perturbations, using which we were able to give a physically clear interpretation of the current-induced spin-orbit torques. We used a toy model mimicking a ferromagnet-topological-insulator interface to illustrate the various effects, and predicted an anisotropic gyromagnetic ratio and the dynamical stability for an in-plane magnetization. Our formalism can also be applied to the slow dynamics of other order parameters in crystalline solids.

5 pages, 2 figure

References in corpus (6)

• Topological Field Theory of Time-Reversal Invariant Insulators
• Spin Transfer Torques
• Spin pumping and spin-transfer torques in antiferromagnets
• Surface quantized anomalous Hall current and magneto-electric effect in magnetically disordered topological insulators
• Spin-orbit torque in 3D topological insulator-ferromagnet heterostructure: crossover between bulk and surface transport
• Spin diffusion and torques in disordered antiferromagnets

Cited by in corpus (5)

• Changes of Magnetism in a Magnetic Insulator due to Proximity to a Topological Insulator
• Topological electric driving of magnetization dynamics in insulators
• Lossless Spin-Orbit Torque in Antiferromagnetic Topological Insulator MnBi${}_2$Te${}_4$
• Voltage-driven exchange resonance achieving 100\% mechanical efficiency
• Néel Spin-Orbit Torque in Antiferromagnetic Quantum Spin and Anomalous Hall Insulators