7 I have tried only a checkerboard antiferromagnetic arrange- ment, since I do not see any a priori reason for any other antiferromagnetic ordering (the fact that the crystal struc- ture coincides with that of pnictide superconductors is not an argument at all that this material would assume the 6 In Ref. 3, unconventional notations for the high symmetry points are used; conventional A ( π, 0 , π ) is called R, and conventional R ( π, π, π ) is called A. I am using the standard notations. 8 I. I. Mazin, Appl. Phys. Lett. 77 , 3000 (2000). 9 P. Larson, I.I. Mazin, D.J. Singh, Phys. Rev. B69 , 064429 (2004). same exotic magnetic structure). Of course, this does not mean that there are no spin fluctuations with a finite wave vector; it only tells us that if such fluctuations occur, they occur at a wave vector, different from π, π (in the unfolded Brillouin zone notation). 0.05 meV. 3