[Pw_forum] Total magnetization and local magnetic moment

Padmaja Patnaik padmaja_patnaik at yahoo.co.uk
Mon Jul 5 12:05:54 CEST 2010


I have proceeded with the supercell which is giving correct DOS. Here is the value of total magnetizatin from the scf.out file without relaxation.

!    total energy              = -1494.09037638 Ry
     Harris-Foulkes estimate   = -1494.09037639 Ry
     estimated scf accuracy    <        6.7E-09 Ry

     The total energy is the sum of the following terms:

     one-electron contribution =   257.19918198 Ry
     hartree contribution      =   202.08158140 Ry
     xc contribution           =  -548.49776710 Ry
     ewald contribution        = -1404.85946098 Ry
     smearing contrib. (-TS)   =    -0.01391169 Ry

     total magnetization       =     1.02 Bohr mag/cell
     absolute magnetization    =     1.12 Bohr mag/cell

     convergence has been achieved in  17 iterations
------------------------------------------------------------------------
Here is the portion of the file *.pdos.out  without relaxation

 Atom #   1: total charge =  14.3653, s =  2.4622, p =  6.8403, d =  5.0628,
                 spin up      =   7.7466, s =  1.2349, p =  3.4229, d =  3.0889,
                 spin down    =   6.6187, s =  1.2274, p =  3.4174, d =  1.9739,
                 polarization =   1.1279, s =  0.0075, p =  0.0054, d =  1.1150,
     Atom #   2: total charge =   2.9244, s =  0.8587, p =  2.0656, d =  0.0000,
                 spin up      =   1.4798, s =  0.4351, p =  1.0446, d =  0.0000,
                 spin down    =   1.4446, s =  0.4236, p =  1.0210, d =  0.0000,
                 polarization =   0.0352, s =  0.0115, p =  0.0236, d =  0.0000,
     Atom #   3: total charge =   2.9244, s =  0.8587, p =  2.0656, d =  0.0000,
                 spin up      =   1.4798, s =  0.4351, p =  1.0446, d =  0.0000,
                 spin down    =   1.4446, s =  0.4236, p =  1.0210, d =  0.0000,
                 polarization =   0.0352, s =  0.0115, p =  0.0236, d =  0.0000,
-----------------------------------------------------------------------------------------------------------------
As you can see atom number 1(this is the impurity) is showing a local magnetic moment. Now, below i add portions of the same two files from with relaxation calculations.
!    total energy              = -1494.15610974 Ry
     Harris-Foulkes estimate   = -1494.15610974 Ry
     estimated scf accuracy    <        1.9E-10 Ry

     The total energy is the sum of the following terms:

     one-electron contribution =   270.52901167 Ry
     hartree contribution      =   195.52169853 Ry
     xc contribution           =  -548.43270406 Ry
     ewald contribution        = -1411.76028316 Ry
     smearing contrib. (-TS)   =    -0.01383273 Ry

     total magnetization       =     1.13 Bohr mag/cell
     absolute magnetization    =     1.26 Bohr mag/cell

     convergence has been achieved in   9 iterations


------------------------------------------------------------------------------------------------------------
Atom #   1: total charge =  19.3947, s =  2.5253, p =  7.6414, d =  9.2280,
                 spin up      =   9.7222, s =  1.2688, p =  3.8289, d =  4.6245,
                 spin down    =   9.6725, s =  1.2566, p =  3.8125, d =  4.6035,
                 polarization =   0.0496, s =  0.0122, p =  0.0164, d =  0.0210,
     Atom #   2: total charge =   3.0599, s =  0.9045, p =  2.1555, d =  0.0000,
                 spin up      =   1.5315, s =  0.4527, p =  1.0787, d =  0.0000,
                 spin down    =   1.5285, s =  0.4517, p =  1.0767, d =  0.0000,
                 polarization =   0.0030, s =  0.0010, p =  0.0020, d =  0.0000,
     Atom #   3: total charge =   3.0599, s =  0.9045, p =  2.1555, d =  0.0000,
                 spin up      =   1.5315, s =  0.4527, p =  1.0787, d =  0.0000,
                 spin down    =   1.5285, s =  0.4517, p =  1.0767, d =  0.0000,
                 polarization =   0.0030, s =  0.0010, p =  0.0020, d =  0.0000,
----------------------------------------------------------------------------------------------------------------------
Here as you can see the total magnetization increases but the atom number 1 (impurity) is showing zero local magnetic moment.
I hope i made the problem more clear this time.

Regards

Message: 2
Date: Mon, 5 Jul 2010 10:42:34 +0200
From: Gabriele Sclauzero <sclauzer at sissa.it>
Subject: Re: [Pw_forum] Total magnetization and local magnetic moment
To: PWSCF Forum <pw_forum at pwscf.org>
Message-ID: <422DE4FD-F788-4D7E-87B0-9975E478EA02 at sissa.it>
Content-Type: text/plain; charset="iso-8859-1"


So, have you managed to converge the DOS first?

Again, if don't post some specific information about your system, as the input files, part of the output files and a sketch of your procedure, it's almost impossible to localize the problem.

GS


Il giorno 04/lug/2010, alle ore 23.09, Padmaja Patnaik ha scritto:

>  Dear all
> 
> I am getting some surprising results. I am calculating for a semiconductor doped with a transition metal ( using single impurity atom in a super cell). The total magnetization value obtained is more than one and so also the local moment on the impurity atom. But when i performed calculations with relaxation, the total magnetic moment increases but the local moment goes to almost zero value, which is very surprising. I expect the local magnetic moment to be almost of the same value as the total. I have also checked other atoms in the super cell, all are showing zero local moments but still the total magnetic moment is increased after relaxation. Let me mention here I am taking the total magnetic moment from the scf.out file and local moments from pdos.out file.
> 
> 
> Please suggest me how to interpret this result? As per my understanding if a sample is showing ferromagnetic results after adding some impurity then it should be reflected on the local magnetic moment of the impurity atom too. In my results, this is the case before relaxation but not after relaxation, which is quite surprising.
> 
> Regards
> Padmaja Patnaik
> Research Scholar
> Dept of Physics
> IIT Bombay
> Mumbai, India
> 
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum


? Gabriele Sclauzero, EPFL SB ITP CSEA
   PH H2 462, Station 3, CH-1015 Lausanne

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Message: 3
Date: Mon, 5 Jul 2010 08:55:21 +0000
From: Masoud Nahali <masoudnahali at live.com>
Subject: [Pw_forum] graphite surface optimizing problem
To: Quantum Espresso <pw_forum at pwscf.org>
Message-ID: <COL114-W147F6600F7FBD86C92902DA1B10 at phx.gbl>
Content-Type: text/plain; charset="windows-1256"


Dear Quantum Espresso users

I optimized the graphite bulk and
the layers were completely flat. But when I try to "relax" the graphite
surface (slab 2*2 with 3 monolayer) with 10 angstrom vacuum the layers
become extremely ripple!!! I can not find the problem. Your help would
be a great gift.

input file:

&CONTROL
  calculation  = "relax",
  pseudo_dir   = "/home/koa/soft/qe4.2/espresso-4.2/pseudo",
  outdir       = "/home/koa/tmp",
  etot_conv_thr= 1.0D-4,
  forc_conv_thr= 1.0D-3,
  nstep=150,
  /
&SYSTEM
  ibrav     = 4,
  a         = 4.9318,
  b         = 4.9318,
  c         = 16.7029,
  cosab     = -0.5,
  cosac     = 1.0,
  cosbc     = 1.0,
  nat       = 24,
  ntyp      = 1,
  ecutwfc   = 40.D0,
  ecutrho   = 400.D0,
  occupations = 'smearing'
  smearing ='mp', 
  degauss = 0.01,
  nspin = 2,
  starting_magnetization(1)= 1.0,
  /
&ELECTRONS
  conv_thr    = 1.D-6,
  mixing_beta = 0.7D0,
  diagonalization = "david",
/
&IONS
 ion_dynamics="bfgs"
/
ATOMIC_SPECIES
C  12.0107  C.star1s-pbe-rrkjus.UPF
ATOMIC_POSITIONS {angstrom}
C    0.000000    0.000000    0.000000
C    2.465900    0.000000    0.000000
C    -1.232950    2.135532    0.000000
C    1.232950    2.135532    0.000000
C    0.000000    1.423688    0.000000
C    -1.232950    3.559220    0.000000
C    2.465900    1.423688    0.000000
C    1.232950    3.559220    0.000000
C    0.000000    0.000000    3.351450
C    2.465900    0.000000    3.351450
C    -1.232950    2.135532    3.351450
C    1.232950    2.135532    3.351450
C    1.232950    0.711844    3.351450
C    0.000000    2.847376    3.351450
C    3.698850    0.711844    3.351450
C    2.465900    2.847376    3.351450
C    0.000000    0.000000    6.702900
C    2.465900    0.000000    6.702900
C    -1.232950    2.135532    6.702900
C    1.232950    2.135532    6.702900
C    0.000000    1.423688    6.702900
C    -1.232950    3.559220    6.702900
C    2.465900    1.423688    6.702900
C    1.232950    3.559220    6.702900
K_POINTS {automatic}
4 4 1 1 1 1


out put (optimized positions):

C        0.000000000  -0.000000000  -0.686394528
C        2.465900000  -0.003714144  -0.758610095
C       -1.229733457   2.137389072  -0.758610095
C        1.229733457   2.137389072  -0.758610095
C        0.000000000   1.427474855  -0.213813075
C       -1.229670488   3.557326573  -0.213813075
C        2.465900000   1.423688000  -0.285079086
C        1.229670488   3.557326573  -0.213813075
C       -0.000000000   0.000000000   3.630366631
C        2.465900000  -0.014904710   3.544792504
C       -1.220042143   2.142984355   3.544792504
C        1.220042143   2.142984355   3.544792504
C        1.220249305   0.704511250   3.106073641
C        0.000000000   2.847376000   3.022325711
C        3.711550695   0.704511250   3.106073641
C        2.465900000   2.862041499   3.106073641
C        0.000000000   0.000000000   7.468882932
C        2.465900000   0.008344370   7.466151214
C       -1.240176436   2.131359815   7.466151214
C        1.240176436   2.131359815   7.466151214
C        0.000000000   1.414904155   6.963129179
C       -1.240557033   3.563611923   6.963129179
C        2.465900000   1.423688000   6.961528237
C        1.240557033   3.563611923   6.963129179



Many Thanks
Masoud Nahali
Sharif University of Technology
                           
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