General method for atomistic spin-lattice dynamics with first principles accuracy

TL;DR

This paper introduces a first-principles computational method combining spin and lattice dynamics for solids, enabling accurate simulations of magnetic and vibrational phenomena with broad applications.

Contribution

A novel, efficient first-principles method for atomistic spin-lattice simulations that integrates density functional theory with spin and molecular dynamics.

Findings

Accurately reproduces magnon and phonon dispersion in bcc Fe.

Demonstrates dissipation-free spin and lattice motion in small magnetic clusters.

Enables study of ultrafast demagnetization and spincaloritronics phenomena.

Abstract

We present a computationally efficient general first-principles based method for spin-lattice simulations for solids. Our method is based on a combination of atomistic spin dynamics and molecular dynamics, expressed through a spin-lattice Hamiltonian where the bilinear magnetic term is expanded to second order in displacement, and all parameters are computed using density functional theory. The effect of first-order spin-lattice coupling on the magnon and phonon dispersion in bcc Fe is reported as an example, and is seen to be in good agreement with previous simulations performed with an empirical potential approach. In addition, we also illustrate the abilities of our method on a more conceptual level, by exploring dissipation-free spin and lattice motion in small magnetic clusters (a dimer, trimer and quadmer). Our method opens the door for quantitative description and understanding of the microscopic origin of many fundamental phenomena of contemporary interest, such as ultrafast demagnetization, magnetocalorics, and spincaloritronics.