Non-linear extension of the dynamical linear response of spins; extended Heisenberg model

TL;DR

This paper introduces an extended Heisenberg model incorporating orbital-dependent spins and retarded spin torque effects, enabling the study of complex spin dynamics beyond traditional models, including damping and nesting effects.

Contribution

The paper presents a novel extended Heisenberg model derived from dynamical linear response functions, capturing effects like Landau damping and Fermi surface nesting.

Findings

Model describes relaxation effects due to Landau damping.

Captures nesting effects of the Fermi surface.

Applicable to high-resolution spin susceptibility analysis.

Abstract

We introduce a new extended Heisenberg model. The model contains the orbital-dependent spins together with the retarded effects of spin torque. The model is directly derived from the dynamical linear response functions on the transversal spin fluctuation. Our model allows us to address effects which are not accessible via the usual Heisenberg model. With the model, we can describe not only the relaxation effects due to the Landau damping caused by the Stoner excitations, but also the nesting effects of the Fermi surface. We discuss possibilities of the extended Heisenberg model based on the high-resolution plots of the spin susceptibility for Fe.