Simultaneous simulations of magnon and phonon dynamics

The atomistic spin-lattice code is up and running and our first paper describing the method has been published. The paper was selected as “Editors’ Suggestion”. Our method represents a computationally efficient general first-principles based method for spin-lattice simulations for solids and clusters. The method is based on a coupling of atomistic spin dynamics and molecular dynamics simulations, expressed through a spin-lattice Hamiltonian, where the bilinear magnetic term is expanded up to second order in displacement. The effect of first order spin- lattice coupling on the magnon and phonon dispersion in bcc Fe is reported as an example, and we observe good agreement with previous simulations. In addition, we also illustrate the coupled spin-lattice dynamics method on a more conceptual level, by exploring dissipation-free spin and lattice motion of small magnetic clusters (a dimer, trimer and quadmer). The here discussed method opens the door for a quantitative description and understanding of the microscopic origin of many fundamental phenomena of contemporary interest, such as ultrafast demagnetization, magnetocalorics, and spincaloritronics.

Image Reference: General method for atomistic spin-lattice dynamics with first-principles accuracy, J. Hellsvik, D. Thonig, K. Modin, D. Iusan, A. Bergman, O. Eriksson, L. Bergqvist, and A. Delin, Phys. Rev B 99, 104302 (2019).