Comment on 'DFT+U search for the energy minimum among eight collinear and noncollinear magnetic structures of GdB_4'

摘要

M. N. Huda and L. Kleinman [Phys. Rev. B 78, 094424 (2008)] suggested that the magnetic structure reported for GdB_4 from spherical neutron polarimetry [J. A. Blanco, P. J. Brown, A. Stunault, K. Katsumata, F. Iga, and S. Michimura, Phys. Rev. B 73, 212411 (2006)]. a noncollinear antiferromagnetic arrangement of the Gd~(3+), whose magnetic space group is P4/m'b'm' may not be the right one. Instead of that proposed from neutron scattering, they concluded based on DFT+U calculations that the ground state corresponds to a collinear arrangement. This conclusion that the DFT+U method leads to a completely magnetic arrangement from that found experimentally demonstrates the limitation of this method when used to predict magnetic structures.