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Fcc Ni (revisited)

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Task

Calculation of the partial DOS of spin-polarized fcc Ni, a ferromagnet.

Input

POSCAR

fcc:                             
 -10.93    
 0.5 0.5 0.0
 0.0 0.5 0.5
 0.5 0.0 0.5
   1  
Cartesian
0 0 0

INCAR

SYSTEM  = Ni fcc bulk 
ISTART  = 0
ISPIN   = 2
MAGMOM  = 1.0
ISMEAR  = -5
VOSKOWN = 1 
LORBIT  = 11
  • Spin-polarized calculation with initial magnetic moment of 1 µB.
  • Interpolation scheme of Vosko, Wilk and Nusair is used (see VOSKOWN=1).
  • lm-decomposed DOSCAR is created.
  • Tetrahedron method with Blöchl's corrections used for k-mesh integration.

KPOINTS

k-points
0
Gamma
 11 11 11
  0  0  0

Calculation

Collinear case

  • The output for the magnetic moments in the OSZICAR should look like the following:
       N        E
DAV:   1     0.139935173959E+02    0.13994E+02   -0.35801E+03  2338   0.828E+02
DAV:   2    -0.623612680591E+01   -0.20230E+02   -0.19281E+02  2282   0.123E+02
DAV:   3    -0.643764005251E+01   -0.20151E+00   -0.19906E+00  2536   0.140E+01
DAV:   4    -0.643786482872E+01   -0.22478E-03   -0.22442E-03  2344   0.459E-01
DAV:   5    -0.643786514671E+01   -0.31798E-06   -0.31687E-06  1832   0.173E-02    0.793E+00
...
DAV:   9    -0.545953126374E+01    0.48409E-02   -0.96206E-03  2946   0.839E-01    0.847E-02
DAV:  10    -0.545946513577E+01    0.66128E-04   -0.77007E-05  1364   0.126E-01
   1 F= -.54594651E+01 E0= -.54594651E+01  d E =0.000000E+00  mag=     0.5781
  • The l decomposed parts of the magnetic moment are written in the OUTCAR file:
 magnetization (x)


# of ion     s       p       p       tot
----------------------------------------
  1       -0.007  -0.026   0.625   0.591
  • The example output for the spin up and down DOS shows an exchange splitting of approximately 0.5 eV:

Fig fccNi revised 1.png

  • Proper initialization of magnetic moments is ver important:
    • Too small initial magnetic moments will/may lead to nonmagnetic solution (by starting with an initial moment of 0.0 we arrive only to a magnetic of 0.002).
    • Badly initialized calculations take longer to converge.
    • Coexistence of low- and high spin solutions.

Noncollinear case

  • For a noncollinear calculation replace ISPIN=2 and MAGMOM=1.0 in the INCAR file by the following:
LNONCOLLINEAR = .TRUE.
MAGMOM        = 0.0 0.0 1.0
  • The last three lines of the OSZICAR file using this parameter should look like the following:
DAV:   9    -0.546480633680E+01    0.41628E-02   -0.49402E-04  7532   0.330E-01    0.695E-02
DAV:  10    -0.546475032360E+01    0.56013E-04   -0.52286E-05  4328   0.446E-02
   1 F= -.54647503E+01 E0= -.54647503E+01  d E =0.000000E+00  mag= 0.0000   0.0000   0.5792
  • By using MAGMOM = 1.0 0.0 0.0 we get the following output:
DAV:   9    -0.546481348871E+01    0.41496E-02   -0.50294E-04  7548   0.330E-01    0.692E-02
DAV:  10    -0.546474438319E+01    0.69106E-04   -0.51451E-05  4288   0.432E-02
   1 F= -.54647444E+01 E0= -.54647444E+01  d E =0.000000E+00  mag= 0.5792   0.0000   0.0000
  • Analogously if we set MAGMOM = 0.0 1.0 0.0 we get the following output:
DAV:   9    -0.546481179459E+01    0.41515E-02   -0.50430E-04  7552   0.330E-01    0.692E-02
DAV:  10    -0.546474640011E+01    0.65394E-04   -0.51658E-05  4292   0.434E-02
   1 F= -.54647464E+01 E0= -.54647464E+01  d E =0.000000E+00  mag= 0.0000   0.5792   0.0000

Download

4_1_Ni.tgz

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