[Pw_forum] magnetism issues
Samin, Adib J.
samin.2 at buckeyemail.osu.edu
Tue Jul 1 16:25:19 CEST 2014
Hello all,
I am trying to calculate the total magnetization and the magnetic moments per atom of iron neodymium boron (NdFeB). The unit cell contains 68 atoms. I first checked convergence with respect to the energy cutoff (to within 1mRy/atom), the k-points, and the number of bands used. The PBE Generalized Gradient exchange correlation functional was used in a spin-polarized calculation. Two separate calculations were performed. In the first calculation no Hubbard U was used and in the second calculation, Hubbard U values were used for both the Nd and Fe atoms to account for the repulsion between localized electrons. I have attached my input file below for the latter case. It is interesting that when I use the Hubbard U, I obtain the "correct" total magnetization which agrees with the literature but the magnetic moments are totally wrong. What is specifically alarming is that the Nd and Fe magnet moment are oriented antiparallel in the Hubbard U calculation (and this is wrong). Without using the Hubbard U, the magnetic moments are parallel to each other but the total magnetization and the individual magnetic moments are still off. Any help with this issue would be greatly appreciated.
&control
calculation='scf'
restart_mode='from_scratch',
wf_collect=.TRUE.,
prefix='NdFeB',
pseudo_dir = '/usr/local/espresso/espresso-5.0.3/pseudo/',
outdir = '/fs/lustre/osu7834/NdFeB/'
/
&system
ibrav=0, nat=68, ntyp=3,
nspin=2, starting_magnetization(1)=0.6, starting_magnetization(2)=0.6, starting_magnetization(3)=0.6,
ecutwfc = 260.0
occupations='smearing', smearing='mv', degauss=0.002
lda_plus_u=.true.
Hubbard_U(1)=6.0, Hubbard_U(2)=2.9
/
&electrons
conv_thr=1.0e-6
mixing_beta=0.02
mixing_mode = 'local-TF'
/
CELL_PARAMETERS {angstrom}
8.8 0.0 0.0
0.0 12.19 0.0
0.0 0.0 8.8
ATOMIC_SPECIES
Nd 144.24 Nd.pbe-mt_fhi.UPF
Fe 55.845 Fe.pbe-mt_fhi.UPF
B 10.811 B.pbe-mt_fhi.UPF
ATOMIC_POSITIONS {angstrom}
B 5.54400 0.00000 3.25600
B 3.25600 0.00000 5.54400
B 7.65600 6.09500 7.65600
B 1.14400 6.09500 1.14400
Fe 4.40000 0.00000 0.00000
Fe 4.40000 6.09500 0.00000
Fe 0.00000 6.09500 4.40000
Fe 0.00000 0.00000 4.40000
Fe 4.40000 1.37747 4.40000
Fe 0.00000 7.47247 0.00000
Fe 0.00000 4.71753 0.00000
Fe 4.40000 10.81253 4.40000
Fe 0.85360 2.49895 0.85360
Fe 7.94640 2.49895 7.94640
Fe 5.25360 8.59395 3.54640
Fe 3.54640 8.59395 5.25360
Fe 5.25360 3.59605 3.54640
Fe 3.54640 3.59605 5.25360
Fe 0.85360 9.69105 0.85360
Fe 7.94640 9.69105 7.94640
Fe 2.79840 3.01093 2.79840
Fe 6.00160 3.01093 6.00160
Fe 7.19840 9.10593 1.60160
Fe 1.60160 9.10593 7.19840
Fe 7.19840 3.08407 1.60160
Fe 1.60160 3.08407 7.19840
Fe 2.79840 9.17907 2.79840
Fe 6.00160 9.17907 6.00160
Fe 4.99840 1.56032 1.97120
Fe 3.80160 1.56032 6.82880
Fe 6.37120 7.65532 8.20160
Fe 2.42880 7.65532 0.59840
Fe 0.59840 4.53468 2.42880
Fe 8.20160 4.53468 6.37120
Fe 1.97120 10.62968 4.99840
Fe 6.82880 1.56032 3.80160
Fe 3.80160 10.62968 6.82880
Fe 4.99840 10.62968 1.97120
Fe 2.42880 4.53468 0.59840
Fe 6.37120 4.53468 8.20160
Fe 8.20160 7.65532 6.37120
Fe 0.59840 7.65532 2.42880
Fe 6.82880 10.62968 3.80160
Fe 1.97120 1.56032 4.99840
Fe 3.15920 2.14544 0.34320
Fe 5.64080 2.14544 8.45680
Fe 4.74320 8.24044 1.24080
Fe 4.05680 8.24044 7.55920
Fe 7.55920 3.94956 4.05680
Fe 1.24080 3.94956 4.74320
Fe 0.34320 10.04456 3.15920
Fe 8.45680 2.14544 5.64080
Fe 5.64080 10.04456 8.45680
Fe 3.15920 10.04456 0.34320
Fe 4.05680 3.94956 7.55920
Fe 4.74320 3.94956 1.24080
Fe 1.24080 8.24044 4.74320
Fe 7.55920 8.24044 4.05680
Fe 8.45680 10.04456 5.64080
Fe 0.34320 2.14544 3.15920
Nd 2.34080 0.00000 2.34080
Nd 6.45920 0.00000 6.45920
Nd 6.74080 6.09500 2.05920
Nd 2.05920 6.09500 6.74080
Nd 7.56800 0.00000 1.23200
Nd 1.23200 0.00000 7.56800
Nd 5.63200 6.09500 5.63200
Nd 3.16800 6.09500 3.16800
K_POINTS {automatic}
4 4 4 0 0 0
Adib Samin
Graduate Fellow
The Department of Mechanical and Aerospace Engineering
The Ohio State University
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20140701/752627f1/attachment.html>
More information about the users
mailing list