Adiabatic and Nonadiabatic Spin-transfer Torques in Antiferromagnets

Abstract

Electron transport in magnetic orders and the magnetic orders dynamics have a mutual dependence, which provides the key mechanisms in spin-dependent phenomena. Recently, antiferromagnetic orders are focused on as the magnetic order, where current-induced spin-transfer torques, a typical effect of electron transport on the magnetic order, have been debatable mainly because of the lack of an analytic derivation based on quantum field theory. Here, we construct the microscopic theory of spin-transfer torques on the slowly-varying staggered magnetization in antiferromagnets with weak canting. In our theory, the electron is captured by bonding/antibonding states, each of which is the eigenstate of the system, doubly degenerates, and spatially spreads to sublattices because of electron hopping. The spin of the eigenstates depends on the momentum in general, and a nontrivial spin-momentum locking arises for the case with no site inversion symmetry, without considering any spin-orbit couplings. The spin current of the eigenstates includes an anomalous component proportional to a kind of gauge field defined by derivatives in momentum space and induces the adiabatic spin-transfer torques on the magnetization. Unexpectedly, we find that one of the nonadiabatic torques has the same form as the adiabatic spin-transfer torque, while the obtained forms for the adiabatic and nonadiabatic spin-transfer torques agree with the phenomenological derivation based on the symmetry consideration. This finding suggests that the conventional explanation for the spin-transfer torques in antiferromagnets should be changed. Our microscopic theory provides a fundamental understanding of spin-related physics in antiferromagnets.

References in corpus (26)

• Antiferromagnetic spintronics
• Antiferromagnetic spintronics
• Static and Dynamical Properties of Antiferromagnetic Skyrmions in the Presence of Applied Current and Temperature
• Giant momentum-dependent spin splitting in centrosymmetric low Z antiferromagnets
• Modification of the Landau-Lifshitz Equation in the Presence of a Spin-Polarized Current in CMR and GMR Materials
• Spin pumping and spin-transfer torques in antiferromagnets
• Microscopic approach to current-driven domain wall dynamics
• Spin transfer and current-induced switching in antiferromagnets
• Phenomenology of Current-Induced Dynamics in Antiferromagnets
• Staggered Dynamics in Antiferromagnets by Collective Coordinates
• Spin transfer in an antiferromagnet
• Anomalous Hall Effect and Skyrmion Number in Real- and Momentum-space
• Spontaneous Antisymmetric Spin Splitting in Noncollinear Antiferromagnets without Spin-Orbit Coupling
• Spin-transfer torques in anti-ferromagnetic metals from first principles
• Effect of Polarized Current on the Magnetic State of Antiferromagnet
• Current-induced torques due to compensated antiferromagnets
• Spin-transfer torques for domain walls in antiferromagnetically coupled ferrimagnets
• Dynamics of Antiferromagnets Driven by Spin Current
• Electron Dynamics in Slowly Varying Antiferromagnetic Texture
• Spin Transfer Torque in Antiferromagnetic Spin-Valves: From Clean to Disordered Regimes
• Distinct trivial phases protected by a point-group symmetry in quantum spin chains
• Spin-transfer torques in antiferromagnets: efficiency and quantification method
• Gauge Field Formulation of Adiabatic Spin Torques
• Microscopic and Macroscopic Signatures of Antiferromagnetic Domain Walls
• Numerical Computation of Spin-Transfer Torques for Antiferromagnetic Domain walls
• Alternating Current-induced Interfacial Spin-transfer Torque

Cited by in corpus (4)

• Microscopic Calculation of Spin Torques in Textured Antiferromagnets
• Current-controlled chirality dynamics in a mesoscopic magnetic domain wall
• Current-Induced Spin-Wave Doppler Shift in Antiferromagnets
• Fast reversal of Néel vectors in antiferromagnets via domain-wall motion driven by vertically injected spin currents