Magnon and Phonon Dispersion, Lifetime and Thermal Conductivity of Iron from Spin-Lattice Dynamics Simulations

TL;DR

This study employs spin-lattice dynamics simulations to analyze magnon and phonon dispersion, lifetimes, and thermal conductivity in ferromagnetic iron, providing insights into coupled spin-lattice transport phenomena.

Contribution

It introduces a novel method combining SLD simulations with spectral energy analysis to evaluate magnon and phonon transport properties in magnetic crystals.

Findings

Calculated magnon and phonon dispersion relations.

Determined scattering rates and lifetimes.

Estimated thermal conductivity of iron.

Abstract

In recent years, the fundamental physics of spin-thermal (i.e., magnon-phonon) interaction has attracted significant experimental and theoretical interests given its potential paradigm-shifting impacts in areas like spin-thermoelectrics, spin-caloritronics and spintronics. Modelling studies of the transport of magnons and phonons in magnetic crystals are very rare. In this paper, we use spin-lattice dynamics (SLD) simulations to model ferromagnetic crystalline iron, where the spin and lattice systems are coupled through the atomic position-dependent exchange function, and thus the interaction between magnon and phonon is naturally considered. We then present a method combining SLD simulations with spectral energy analysis to calculate the magnon and phonon harmonic (e.g., dispersion, specific heat, group velocity) and anharmonic (e.g., scattering rate) properties, based on which their thermal conductivity values are calculated. This work represents an example of using SLD simulations to understand the transport properties involving coupled magnon and phonon dynamics.