pair_style spin/me command


pair_style spin/me cutoff
  • cutoff = global cutoff pair (distance in metal units)


pair_style spin/me 4.5
pair_coeff * * me 4.5 0.00109 1.0 1.0 1.0


Style spin/me computes a magneto-electric interaction between pairs of magnetic spins. According to the derivation reported in (Katsura), this interaction is defined as:


where si and sj are neighboring magnetic spins of two particles, eij = (ri - rj)/|ri-rj| is the normalized separation vector between the two particles, and E is an electric polarization vector. The norm and direction of E are giving the intensity and the direction of a screened dielectric atomic polarization (in eV).

From this magneto-electric interaction, each spin i will be submitted to a magnetic torque omega, and its associated atom can be submitted to a force F for spin-lattice calculations (see fix_nve_spin), such as:


with h the Planck constant (in metal units).

More details about the derivation of these torques/forces are reported in (Tranchida).


All the pair/spin styles are part of the SPIN package. These styles are only enabled if LAMMPS was built with this package, and if the atom_style “spin” was declared. See the Making LAMMPS section for more info.