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

A computationally efficient general first-principles based method is presented, with applications for spin-lattice simulations for solids and clusters. The 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. 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.