Parallel implementation of spin and spin-lattice simulations in LAMMPS

Julien Tranchida, Aidan P. Thompson

Multiscale Science Department, Sandia National Laboratories,P.O. Box 5800, MS 1322, Albuquerque, NM 87185

jtranch at sandia.gov

Deriving from the DFT formalism, a semi-classical methodology referred
to as spin dynamics (SD) can be used as a reliable tool for the
simulation of the magnetization dynamics in systems containing a large
number of interacting magnetic spins **1**, like spin lattices **2**, or
spin liquids **3**. More recently, it has also been shown possible to
couple spin degrees of freedom to lattice vibrations by combining the
formalism of molecular dynamics to spin dynamics **4**, using empirical
potentials **5**. The goal of our project is to construct an efficient
parallel implementation of SD in Sandia's widely-used LAMMPS molecular
dynamics code **6**. This will allow spin-lattice simulations to use
parallel computers to access length and timescales much larger than
currently possible. This work will leverage LAMMPS' sophisticated
integration algorithms and the highly parallel structures.

Keywords: Magnetization dynamics, Spin-lattice simulations, Molecular dynamics

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**2** Olle Eriksson, Anders Bergman, Johan Hellsvik, and Lars
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applications. Oxford University Press, 2017.

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**6** Steve Plimpton, Paul Crozier, and Aidan
Thompson. Lammps-large-scale atomic/molecular massively parallel
simulator. Sandia National Laboratories, 18, 2007.