[Pw_forum] pdos-up different from pdos-down for AFM systems

[stefano de gironcoli]

dear Juliana,

Is the system metallic or does your calculation have a gap?

The charges and magnetization values on different atoms are not exactly 
the same so it seams that they are not in equivalent positions. So they 
could have non equivalent pdos.
Have you examined pdos of individual atoms ?

The total magnetization comes from the partially filled 4f electrons of Ce.
If the system has a gap then exactly one f-related band would be fully 
occupied in the up and dw bands and the total magnetization would be 0 
even if the individual atoms are not
equivalent. If there is no gap a complete compensation between up and dw 
states is more strange.

stefano

On 03/10/2015 19:32, Juliana Morbec wrote:
> Dear Stefano.
>
> Thanks for your reply.
> I am using wf_collect = .true. and the same number of processors for 
> both pw.x and projwfc.x calculations:
>      Parallel version (MPI), running on    80 processors
>      K-points division:     npool     =      10
>      R & G space division:  proc/nbgrp/npool/nimage =       8
>      wavefunctions fft division:  fft and procs/group =     4      2
>
> I tried versions v.5.2.0 and v.5.1.1. In both cases I got total 
> magnetization equal to zero:
>
>      Magnetic moment per site:
>      atom:    1    charge:    6.0865    magn:   -0.0022  constr:    0.0000
>      atom:    2    charge:    6.2503    magn:    0.0063  constr:    0.0000
>      atom:    3    charge:    7.1620    magn:    0.9237  constr:    0.0000
>      atom:    4    charge:    6.2496    magn:   -0.0045  constr:    0.0000
>      atom:    5    charge:    7.1708    magn:   -0.9309  constr:    0.0000
>
>      total magnetization       =     0.00 Bohr mag/cell
>      absolute magnetization    =     2.13 Bohr mag/cell
>
> but in the pdos.dat.pdos_tot pdos-up is different from pdos-down:
>
> # E (eV)  dosup(E)   dosdw(E)  pdosup(E)  pdosdw(E)
> -21.980  0.181E-04  0.835E-05  0.181E-04  0.835E-05
> -21.930  0.128E-02  0.689E-03  0.128E-02  0.689E-03
> -21.880  0.342E-01  0.212E-01  0.342E-01  0.212E-01
> -21.830  0.361E+00  0.256E+00  0.361E+00  0.256E+00
> -21.780  0.170E+01  0.135E+01  0.170E+01  0.135E+01
> -21.730  0.434E+01  0.374E+01  0.434E+01  0.374E+01
> -21.680  0.658E+01  0.627E+01  0.658E+01  0.627E+01
> -21.630  0.509E+01  0.570E+01  0.509E+01  0.570E+01
> -21.580  0.167E+01  0.228E+01  0.167E+01  0.228E+01
> -21.530  0.210E+00  0.355E+00  0.210E+00  0.355E+00
> ...
>
> In the input file I am trying the AFM configuration:
>
>   nspin = 2
>   starting_magnetization(1) = 1.0
>   starting_magnetization(2) = -1.0
>
> where species 1 and 2 are Ce atoms (Ce1 and Ce2).
>
> As the total_magnetization is equal to zero, I was expecting to obtain 
> pdos-up = pdos-down. I don't understand what I am doing wrong. I 
> really appreciate any help you can provide.
>
> Best wishes,
>
> Juliana Morbec
>
> On Sat, Oct 3, 2015 at 1:39 AM stefano de gironcoli <degironc at sissa.it 
> <mailto:degironc at sissa.it>> wrote:
>
>     A recent commit on SVN says:
>     'When pw was run with different nproc and twfcollect was not true,
>     the code was still running without giving error and was executing
>     wrongly with missing data.Thanks to Hande Toffoli for reporting.'
>
>     A run time check has been added on the SVN version as of yesterday.
>
>     Are you using twfcollect option or are you sure you are using the
>     same parallel configuration
>     in the pw.x and in the pp.x calculation ?
>
>     HTH
>
>     stefano
>
>
>
>     On 03/10/2015 04:29, Juliana Morbec wrote:
>>     Hello.
>>
>>     I am computing pdos of AFM Ce2O3, and although I obtained total
>>     magnetic moment equal to zero, the pdos up is different from pdos
>>     down. Does anyone have any idea why this happens?
>>
>>     I really appreciate any help.
>>
>>     Best,
>>
>>     Juliana Morbec
>>     Postdoc
>>     University of Chicago
>>
>>
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