Atomistic Spin-Lattice Dynamics

Abstract

Finite temperature magnetic fluctuations determine a variety of properties of magnetic materials, including their phase stability, their thermodynamic properties, and even the structure of defects formed under irradiation. A fundamental feature of microscopic magnetic fluctuations is the directional non-collinearity of fluctuating atomic magnetic moments, which stems from the rotational invariance of an atomic magnetic Hamiltonian. To model the dynamics of magnetic moments of atoms that move themselves, a fast and computationally efficient simulation approach is required. Spin-lattice dynamics simulates atomic movements as well as rotational and longitudinal fluctuations of atomic magnetic moments within a unified framework, generalizing molecular dynamics to magnetic materials. Collective magnetic and atomic excitations can now be investigated on the microscopic scale, similarly to how transformations of atomic structures can be investigated using molecular dynamics simulations. This chapter outlines theoretical foundations and numerical algorithms of spin-lattice dynamics and describes applications of the method.