[Pw_forum] scf calculation for Cr_2O_3

y.satono.851 y.satono.851 at ms.saitama-u.ac.jp
Fri Jul 7 07:52:45 CEST 2017


Dear QE users,

 I am trying to run a scf calculation for Cr_2O_3 by LDA+U with 6.1 version of PWSCF. 
 Cr_2O_3 has four magnetic Cr^3+ ions in the rhombohedral unit cell. 
 It develops collinear spin ordering below a Neel temperature.
 To fix the mangetic structure at this one below the Neel temperature,
 I constrained the angles of the magnetic moments.

 Input file and last few outputs of total energy and total magnetization are given below.
 I have changed the value of cutoff energy, iterations and mixing beta, but total energy and total magnetization did not converged.
 In particular, the magnetic moments showed some oscillation.

 How can I fix the problem?

 I would appreciate any suggestions.


 _____Input file_____
 &CONTROL
  Calculation=’scf’
 Verbosity=’high’
 tstress=.true.
  tprnfor = .true.
  pseudo_dir = './',
  outdir='./work/'
  disk_io='low'
  wf_collect=.true.
 /
 &SYSTEM
  ibrav = 0
  A =    4.95400
  nat = 10
  ntyp = 5
  nspin = 4
  constrained_magnetization = "atomic direction"
  noncolin = .True.
  lspinorb = .True.
  lambda = 1.0
  angle1(1) = 180
  angle1(2) = 0
  angle1(3) = 180
  angle1(4) = 0
  ecutwfc = 60.0,
  ecutrho = 250.0
  occupations = 'smearing'
  smearing = 'm-p'
  degauss = 0.01
  lda_plus_u = .True.
  lda_plus_u_kind = 1
  Hubbard_U(1)=2.0
  Hubbard_U(2)=2.0
  Hubbard_U(3)=2.0
  Hubbard_U(4)=2.0
 /
 &electrons
  electron_maxstep = 200
  mixing_beta = 0.7
  conv_thr = 1.0d-8
 /
 CELL_PARAMETERS {alat}
   0.577350269189626   0.000000000000000   0.914008881711748
  -0.288675134594813   0.500000000000000   0.914008881711748
  -0.288675134594813  -0.500000000000000   0.914008881711748
 ATOMIC_SPECIES
   Cr1   51.99610  Cr.rel-pz-spn-kjpaw_psl.0.2.3.UPF
   Cr2   51.99610  Cr.rel-pz-spn-kjpaw_psl.0.2.3.UPF
   Cr3   51.99610  Cr.rel-pz-spn-kjpaw_psl.0.2.3.UPF
   Cr4   51.99610  Cr.rel-pz-spn-kjpaw_psl.0.2.3.UPF
   O   15.99900   O.rel-pz-n-kjpaw_psl.0.1.UPF
 ATOMIC_POSITIONS {crystal}
 Cr1   0.147830000000000   0.147830000000000   0.147830000000000
 Cr2   0.352170000000000   0.352170000000000   0.352170000000000
 Cr3   0.647830000000000   0.647830000000000   0.647830000000000
 Cr4   0.852170000000000   0.852170000000000   0.852170000000000
  O    0.556180000000000   0.943820000000000   0.250000000000000
  O    0.943820000000000   0.250000000000000   0.556180000000000
  O    0.250000000000000   0.556180000000000   0.943820000000000
  O    0.750000000000000   0.443820000000000   0.056180000000000
  O    0.056180000000000   0.750000000000000   0.443820000000000
  O    0.443820000000000   0.056180000000000   0.750000000000000
 K_POINTS {automatic}
 4 4 4 0 0 0 

 _____Output total energy and total magnetization_____
      total energy              =   -1221.08594787 Ry      total magnetization       =     0.00     0.00    -0.00 Bohr mag/cell
      total energy              =   -1221.08594804 Ry      total magnetization       =     0.00    -0.00    -0.00 Bohr mag/cell
      total energy              =   -1221.08594807 Ry      total magnetization       =     0.00     0.00    -0.00 Bohr mag/cell
      total energy              =   -1221.08640028 Ry      total magnetization       =    -0.00     0.00    -0.00 Bohr mag/cell
      total energy              =   -1220.84342810 Ry      total magnetization       =    -0.00    -0.00     0.04 Bohr mag/cell
      total energy              =   -1221.08596525 Ry      total magnetization       =     0.00    -0.00    -0.00 Bohr mag/cell
      total energy              =   -1221.08331195 Ry      total magnetization       =    -0.00     0.00     0.00 Bohr mag/cell
      total energy              =   -1220.81290900 Ry      total magnetization       =    -0.00    -0.00     0.03 Bohr mag/cell
      total energy              =   -1220.93168616 Ry      total magnetization       =     0.00     0.00     0.03 Bohr mag/cell
      total energy              =   -1220.43732201 Ry      total magnetization       =     0.00     0.00     0.23 Bohr mag/cell
      total energy              =   -1221.08594708 Ry      total magnetization       =     0.00    -0.00    -0.00 Bohr mag/cell
      total energy              =   -1221.08594855 Ry      total magnetization       =    -0.00     0.00    -0.00 Bohr mag/cell
      total energy              =   -1221.08594859 Ry      total magnetization       =    -0.00    -0.00    -0.00 Bohr mag/cell
      total energy              =   -1221.08644499 Ry      total magnetization       =    -0.00     0.00    -0.00 Bohr mag/cell
      total energy              =   -1220.47536017 Ry      total magnetization       =    -0.00     0.00     0.21 Bohr mag/cell
      total energy              =   -1221.08595082 Ry      total magnetization       =    -0.00    -0.00    -0.00 Bohr mag/cell
      total energy              =   -1221.08629226 Ry      total magnetization       =    -0.00     0.00    -0.00 Bohr mag/cell
      total energy              =   -1220.70585934 Ry      total magnetization       =     0.00     0.00     0.03 Bohr mag/cell
      total energy              =   -1220.93001351 Ry      total magnetization       =    -0.00    -0.00     0.03 Bohr mag/cell
      total energy              =   -1220.01179620 Ry      total magnetization       =     0.00    -0.00     0.60 Bohr mag/cell
      total energy              =   -1221.08594896 Ry      total magnetization       =     0.00     0.00    -0.00 Bohr mag/cell
      total energy              =   -1221.08594900 Ry      total magnetization       =     0.00    -0.00    -0.00 Bohr mag/cell
      total energy              =   -1221.08594902 Ry      total magnetization       =    -0.00     0.00    -0.00 Bohr mag/cell
      total energy              =   -1221.08613508 Ry      total magnetization       =    -0.00     0.00    -0.00 Bohr mag/cell
      total energy              =   -1220.86939998 Ry      total magnetization       =     0.00    -0.00     0.04 Bohr mag/cell
      total energy              =   -1221.08594902 Ry      total magnetization       =     0.00    -0.00    -0.00 Bohr mag/cell
      total energy              =   -1221.08627560 Ry      total magnetization       =    -0.00    -0.00    -0.00 Bohr mag/cell
      total energy              =   -1220.47544823 Ry      total magnetization       =     0.00     0.00     0.08 Bohr mag/cell
      total energy              =   -1220.92213119 Ry      total magnetization       =     0.00     0.00     0.03 Bohr mag/cell
      total energy              =   -1219.57572854 Ry      total magnetization       =    -0.00    -0.00     1.15 Bohr mag/cell



 Yuuki Satono
 University of Saitama
 E-mail  y.satono.851 at ms.saitama-u.ac.jp






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