Microscopic Calculation of Spin Torques and Forces

H. Kohno; G. Tatara; J. Shibata; Y. Suzuki

doi:10.1016/j.jmmm.2006.10.928

Home/Archive/arXiv

arXiv · cond-mat/0611669

Microscopic Calculation of Spin Torques and Forces

H. Kohno·G. Tatara·J. Shibata·Y. Suzuki

View original source ↗Read source document ↗Export metadata ↓

Abstract

Spin torques, that is, effects of conduction electrons on magnetization dynamics, are calculated microscopically in the first order in spatial gradient and time derivative of magnetization. Special attention is paid to the so-called β-term and the Gilbert damping, α, in the presence of electrons' spin-relaxation processes, which are modeled by quenched magnetic impurities. Two types of forces that the electric/spin current exerts on magnetization are identified based on a general formula relating the force to the torque.

Explore related subjects

cond-mat.mes-hall cond-mat.mtrl-sci

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

H. Kohno, G. Tatara, J. Shibata, Y. Suzuki. 2006-11-27. Microscopic Calculation of Spin Torques and Forces. https://doi.org/10.1016/j.jmmm.2006.10.928

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Photoinduced topological phase transition in monolayer 1T$^\prime$-MoS$_2$

We investigate the systematic competition between perpendicular electric field and circularly polarized light in nonequilibrium topological phases of monolayer 1T$^\prime$--MoS$_2$ using a low-energy $k\!\cdot\!p$ Hamiltonian and Floquet theory. The off-resonant field generates spin- and valley-dependent mass corrections that reshape the Berry curvature (BC) and shift the conditions for band inversion. By evaluating the quasienergy bands, BC, and spin- valley-resolved Chern numbers, we identify a sequence of light and electric field controlled topological transitions by gap closing. Depending on the Floquet coupling strength and the electric-field parameter, the system evolves between the equilibrium quantum spin Hall (QSH) state and a set of driven phases including spin-polarized quantum Hall insulator (S-QHI), band insulator (BI) and photo-induced quantum Hall insulator (P-QHI) regimes. The results establish 1T$^\prime$--MoS$_2$ as a tunable platform where circular driving selectively manipulates spin and valley degrees of freedom, enabling controlled access to non-equilibrium topological phases in transition metal dichalcogenides (TMDs).

cond-mat.mes-hall↗

arXiv2026

Engineering Fractional Topological Superconductors: Numerical Bogoliubov-de Gennes Analysis for Parafermion Realization in FCI-Superconductor Heterostructures

We propose a pathway to engineer Z3 parafermion zero modes in fractional Chern insulator-superconductor heterostructures. Using numerical Bogoliubov-de Gennes calculations and edge-theory analysis, we demonstrate how realistic materials such as MoTe2/NbSe2 can host parafermionic excitations with experimentally accessible signatures, including fractional Josephson effects, localized zero modes, interferometry, and thermal transport. Our work outlines concrete strategies for experimentally accessing parafermionic excitations in FCI-superconductor heterostructures.

cond-mat.mes-hall↗

arXiv2026

Disentangling Spin Pumping and Two-Magnon Scattering Contributions to Gilbert Damping in YIG/V Bilayers

In this work, we investigate the magnetic damping and spin pumping response of YIG-based bilayers incorporating vanadium (V) as the normal metal layer via broadband ferromagnetic resonance (FMR) measurements as a function of YIG thickness. We show that the apparent enhancement of the Gilbert damping in YIG/V bilayers cannot be solely attributed to spin pumping. Instead, two-magnon scattering (TMS) plays a dominant role in governing the thickness dependence of the damping in the nanometer regime. By applying a thickness-dependent damping model that accounts for both spin pumping and two-magnon scattering contributions, we successfully disentangle the different relaxation contributions. Our analysis reveals that neglecting two-magnon scattering leads to an overestimation of the spin-pumping contribution and consequently to unphysically large values of the effective spin-mixing conductance. After isolating the intrinsic spin pumping contribution, we extract a thickness-independent effective spin-mixing conductance of $g^{\uparrow\downarrow}_{\mathrm{eff}} = 1.33 \times 10^{18}~\mathrm{m^{-2}}$. These findings provide a more accurate framework for quantifying spin transport parameters in FM/HM systems and emphasize the necessity of accounting for extrinsic damping mechanisms when interpreting spin pumping and inverse spin Hall effect experiments.

cond-mat.mes-hall↗