inter-atomic exchange coupling constant

[baizq]

Hi All,

Is there a way to calculate the exchange coupling constant between any pairs of atoms in a magnetic bulk system? E.g., If I have a Iron bulk system, how could I know the exchange coupling between the nearest neighbors, the second nearest neighbors, and so on? Thank you in advance.

baizq

[zh]

1) build a super cell with sufficient size.
2) do a ferromagnetic calculations for your system;
3) choose one atom and let its spin antiparallel to other atoms, then do the calculations. In this case, sometimes constraint calculations are needed. For example, the total spin should be smaller than that obtained in the 2nd step.