[Pw_forum] Magnetization in 2-atom unit cell/corresponding supercell

Ricardo Afonso ricardo at df.ufscar.br
Tue Aug 8 18:17:35 CEST 2017


Dear Raji,

I have run your input files for xcrysden and repeat the assymmetric unit
for translation.
Aparently a few atoms may be missing along y-axis direction, as you may see
in the attached file below. (right sided figure for 128 supercell with 2
repetition for both directions and left sided figures for 2-atoms cell with
10 repetition of the unit on both directions)
I haven't looked through all the 128-atom positions in your input file, but
I think it is worthy for you. I could not find any mistake for other input
parameters so far.

Regards,

Ricardo.

On 8 August 2017 at 11:12, Raji Abdulrafiu <tunderaji at gmail.com> wrote:

> ​Dear colleagues
>
>
>> thanks for your responses. I provide the scf file for 2-atom cell and the
>> corresponding 128-atom supercell, respectively.
>> ​ ​
>>
>>
> I emphasize that ​
>>  for the 2-atom cell, i obtained the following:
>>
>
> *   ​ ​*t
> ​​
> otal magnetization       =
> ​  ​
>   -0.00 Bohr mag/cell
>      absolute magnetization    =     0.00 Bohr mag/cell
>
> ​ and for the 128-atom supercell, the following was obtained:
>
>>
> ​ ​
> total magnetization       =    10.49 Bohr mag/cell
>      absolute magnetization    =    12.94 Bohr mag/cell
>
> ​Thank you.​
>
> Abdulrafiu Tunde RAJI
>>> School of Interdisciplinary Research and Graduate
> ​ ​
> Studies (SIRCGS),
> University of South Africa (UNISA),
> Mucklenuek
> ​,​
>
> Pretoria 0003,
> South Africa.
>
>>>>
>> ***2-atom cell*****​
>>
>>
> &control
>>     calculation='scf'
>>     restart_mode='from_scratch',
>>     pseudo_dir = '../pseudos_silic/',
>>     outdir='./scr.Silicene'
>>     prefix='Si'
>>     tprnfor = .true.,
>>     tstress = .true.
>>  /
>>
>>  &system
>>     ibrav=0,
>>     celldm(1) = 7.32044250487141336354,
>>     nat=2,
>>     ntyp=1,
>>     nspin = 2,
>>     ecutwfc=50
>>     ecutrho = 600.0,
>>     occupations='smearing',
>>     smearing='methfessel-paxton',
>>     starting_magnetization(1) = 1.0
>>     degauss=0.015
>>
>>  /
>>  &electrons
>>     diagonalization='david'
>>     conv_thr = 1.0e-8
>>     mixing_beta = 0.5
>>     mixing_mode = 'local-TF'
>>     electron_maxstep = 300
>> ! /
>> !&ions
>> ! ion_dynamics = 'bfgs'
>> /
>> ATOMIC_SPECIES
>> Si  28.0855 Si.pbe-n-van.UPF
>>
>> ATOMIC_POSITIONS  angstrom
>>  Si   0.0        0.       0.0
>>  Si   -1.935    -1.1171727531     0.44
>>
>> CELL_PARAMETERS hexagonal
>> 1             0.00              0.00
>> 0.500000     -0.86602540378     0.00
>> 0.00          0.00              4.64452797455544311118
>>
>> K_POINTS automatic
>> 12      12       1       0        0       0
>> --------------------------------------------------------------
>>
>> ​**128 -atom cell****
>> -------------
>> &control
>>     calculation='scf'
>>     restart_mode='from_scratch',
>>     pseudo_dir = '/home/rajiat/workdir_silicine/pseudos_si/',
>>     outdir='./scr.Silicene/Sik331_scr'
>>     prefix='Si_k331'
>>     tprnfor = .true.,
>>     tstress = .true.
>>  /
>>
>>  &system
>>     ibrav=0,
>>     celldm(1) = 58.56351789910827601793,
>>     nat=128,
>>    ! lspinorb=.true.
>>    ! noncolin = .true.
>>     starting_magnetization(1)=0.1
>>     nbnd  = 400
>>     ntyp=1,
>>     nspin = 2,
>>     ecutwfc=50
>>     ecutrho = 600.0,
>>     occupations='smearing',
>>     smearing='methfessel-paxton',
>>     degauss=0.015
>>
>>  /
>>  &electrons
>>     diagonalization='david'
>>     conv_thr = 1.0e-8
>>     mixing_beta = 0.5
>>     mixing_mode = 'local-TF'
>>     electron_maxstep = 300
>> ! /
>> ! &ions
>> ! ion_dynamics = 'bfgs'
>> /
>> ATOMIC_SPECIES
>> Si  28.0855 Si.pbe-n-van.UPF
>>
>> ATOMIC_POSITIONS  angstrom
>>    Si    0.0006187590    0.0003572410   -0.0002053100
>>    Si   -1.9356187590   -1.1175299940    0.4402053100
>>    Si    1.9375236610   -3.3544604580   -0.0002053100
>>    Si   0.0012861430   -4.4723476930    0.4402053100
>>    Si    3.8744285630   -6.7092781570   -0.0002053100
>>    Si    1.9381910450   -7.8271653920    0.4402053100
>>    Si    5.8113334650  -10.0640958560   -0.0002053100
>>    Si    3.8750959470  -11.1819830910    0.4402053100
>>    Si    7.7482383670  -13.4189135550   -0.0002053100
>>    Si    5.8120008490  -14.5368007900    0.4402053100
>>    Si    9.6851432690  -16.7737312540   -0.0002053100
>>    Si    7.7489057510  -17.8916184890    0.4402053100
>>    Si   11.6220481710  -20.1285489530   -0.0002053100
>>    Si    9.6858106530  -21.2464361880    0.4402053100
>>    Si   13.5589530730  -23.4833666520   -0.0002053100
>>    Si   11.6227155550  -24.6012538870    0.4402053100
>>    Si    3.8744285620    0.0003572410   -0.0002053100
>>    Si    1.9381910440   -1.1175299940    0.4402053100
>>    Si    5.8113334640   -3.3544604580   -0.0002053100
>>    Si    3.8750959460   -4.4723476930    0.4402053100
>>    Si    7.7482383660   -6.7092781570   -0.0002053100
>>    Si    5.8120008480   -7.8271653920    0.4402053100
>>    Si    9.6851432680  -10.0640958560   -0.0002053100
>>    Si    7.7489057500  -11.1819830910    0.4402053100
>>    Si   11.6220481700  -13.4189135550   -0.0002053100
>>    Si    9.6858106520  -14.5368007900    0.4402053100
>>    Si   13.5589530720  -16.7737312540   -0.0002053100
>>    Si   11.6227155540  -17.8916184890    0.4402053100
>>    Si   15.4958579740  -20.1285489530   -0.0002053100
>>    Si   13.5596204560  -21.2464361880    0.4402053100
>>    Si   17.4327628760  -23.4833666520   -0.0002053100
>>    Si   15.4965253580  -24.6012538870    0.4402053100
>>    Si    7.7482383650    0.0003572410   -0.0002053100
>>    Si    5.8120008470   -1.1175299940    0.4402053100
>>    Si    9.6851432670   -3.3544604580   -0.0002053100
>>    Si    7.7489057490   -4.4723476930    0.4402053100
>>    Si   11.6220481690   -6.7092781570   -0.0002053100
>>    Si    9.6858106510   -7.8271653920    0.4402053100
>>    Si   13.5589530710  -10.0640958560   -0.0002053100
>>    Si   11.6227155530  -11.1819830910    0.4402053100
>>    Si   15.4958579730  -13.4189135550   -0.0002053100
>>    Si   13.5596204550  -14.5368007900    0.4402053100
>>    Si   17.4327628750  -16.7737312540   -0.0002053100
>>    Si   15.4965253570  -17.8916184890    0.4402053100
>>    Si   19.3696677770  -20.1285489530   -0.0002053100
>>    Si   17.4334302590  -21.2464361880    0.4402053100
>>    Si   21.3065726790  -23.4833666520   -0.0002053100
>>    Si   19.3703351610  -24.6012538870    0.4402053100
>>    Si   11.6220481680    0.0003572410   -0.0002053100
>>    Si    9.6858106500   -1.1175299940    0.4402053100
>>    Si   13.5589530700   -3.3544604580   -0.0002053100
>>    Si   11.6227155520   -4.4723476930    0.4402053100
>>    Si  15.4958579720   -6.7092781570   -0.0002053100
>>    Si   13.5596204540   -7.8271653920    0.4402053100
>>    Si   17.4327628740  -10.0640958560   -0.0002053100
>>    Si   15.4965253560  -11.1819830910    0.4402053100
>>    Si   19.3696677760  -13.4189135550   -0.0002053100
>>    Si   17.4334302580  -14.5368007900    0.4402053100
>>    Si   21.3065726780  -16.7737312540   -0.0002053100
>>    Si   19.3703351600  -17.8916184890    0.4402053100
>>    Si  23.2434775800  -20.1285489530   -0.0002053100
>>    Si   21.3072400620  -21.2464361880    0.4402053100
>>    Si   25.1803824820  -23.4833666520   -0.0002053100
>>    Si   23.2441449640  -24.6012538870    0.4402053100
>>    Si   15.4958579710    0.0003572410   -0.0002053100
>>    Si   13.5596204530   -1.1175299940    0.4402053100
>>    Si   17.4327628730   -3.3544604580   -0.0002053100
>>    Si   15.4965253550   -4.4723476930    0.4402053100
>>    Si   19.3696677750   -6.7092781570   -0.0002053100
>>    Si   17.4334302570   -7.8271653920    0.4402053100
>>    Si   21.3065726770  -10.0640958560   -0.0002053100
>>    Si   19.3703351590  -11.1819830910    0.4402053100
>>    Si   23.2434775790  -13.4189135550   -0.0002053100
>>    Si   21.3072400610  -14.5368007900    0.4402053100
>>    Si   25.1803824810  -16.7737312540   -0.0002053100
>>    Si   23.2441449630  -17.8916184890    0.4402053100
>>    Si   27.1172873830  -20.1285489530   -0.0002053100
>>    Si   25.1810498650  -21.2464361880    0.4402053100
>>    Si   29.0541922850  -23.4833666520   -0.0002053100
>>    Si   27.1179547670  -24.6012538870    0.4402053100
>>    Si   19.3696677740    0.0003572410   -0.0002053100
>>    Si   17.4334302560   -1.1175299940    0.4402053100
>>    Si   21.3065726760   -3.3544604580   -0.0002053100
>>    Si   19.3703351580   -4.4723476930    0.4402053100
>>    Si   23.2434775780   -6.7092781570   -0.0002053100
>>    Si   21.3072400600   -7.8271653920    0.4402053100
>>    Si   25.1803824800  -10.0640958560   -0.0002053100
>>    Si   23.2441449620  -11.1819830910    0.4402053100
>>    Si   27.1172873820  -13.4189135550   -0.0002053100
>>    Si   25.1810498640  -14.5368007900    0.4402053100
>>    Si   29.0541922840  -16.7737312540   -0.0002053100
>>    Si   27.1179547660  -17.8916184890    0.4402053100
>>    Si   30.9910971860  -20.1285489530   -0.0002053100
>>    Si   29.0548596680  -21.2464361880    0.4402053100
>>    Si   32.9280020880  -23.4833666520   -0.0002053100
>>    Si   30.9917645700  -24.6012538870    0.4402053100
>>    Si   23.2434775770    0.0003572410   -0.0002053100
>>    Si   21.3072400590   -1.1175299940    0.4402053100
>>    Si   25.1803824790   -3.3544604580   -0.0002053100
>>    Si   23.2441449610   -4.4723476930    0.4402053100
>>    Si   27.1172873810   -6.7092781570   -0.0002053100
>>    Si   25.1810498630   -7.8271653920    0.4402053100
>>    Si   29.0541922830  -10.0640958560   -0.0002053100
>>    Si   27.1179547650  -11.1819830910    0.4402053100
>>    Si   30.9910971850  -13.4189135550   -0.0002053100
>>    Si   29.0548596670  -14.5368007900    0.4402053100
>>    Si   32.9280020870  -16.7737312540   -0.0002053100
>>    Si   30.9917645690  -17.8916184890    0.4402053100
>>    Si   34.8649069890  -20.1285489530   -0.0002053100
>>    Si   32.9286694710  -21.2464361880    0.4402053100
>>    Si   36.8018118910  -23.4833666520   -0.0002053100
>>    Si   34.8655743730  -24.6012538870    0.4402053100
>>    Si   27.1172873800    0.0003572410   -0.0002053100
>>    Si   25.1810498620   -1.1175299940    0.4402053100
>>    Si   29.0541922820   -3.3544604580   -0.0002053100
>>    Si   27.1179547640   -4.4723476930    0.4402053100
>>    Si   30.9910971840   -6.7092781570   -0.0002053100
>>    Si   29.0548596660   -7.8271653920    0.4402053100
>>    Si   32.9280020860  -10.0640958560   -0.0002053100
>>    Si   30.9917645680  -11.1819830910    0.4402053100
>>    Si   34.8649069880  -13.4189135550   -0.0002053100
>>    Si   32.9286694700  -14.5368007900    0.4402053100
>>    Si   36.8018118900  -16.7737312540   -0.0002053100
>>    Si   34.8655743720  -17.8916184890    0.4402053100
>>    Si   38.7387167920  -20.1285489530   -0.0002053100
>>    Si   36.8024792740  -21.2464361880    0.4402053100
>>    Si   40.6756216940  -23.4833666520   -0.0002053100
>>    Si   38.7393841760  -24.6012538870    0.4402053100
>>
>> CELL_PARAMETERS hexagonal
>> 1.0000000000     0.0000000000        0.0000000000
>> .50000000012907190219    -1.000000000        0.0000000000
>> 0.0000000000     0.0000000000        .64535951095583512312
>>
>> K_POINTS automatic
>> 3        3        1       0        0       0​
>>
>>
>> Message: 6
>>
> Date: Mon, 7 Aug 2017 15:25:10 -0300
>> From: Ricardo Afonso <ricardo at df.ufscar.br>
>> Subject: Re: [Pw_forum] Magnetization in 2-atom unit
>>         cell/corresponding      supercell*
>> To: PWSCF Forum <pw_forum at pwscf.org>
>> Message-ID:
>>         <CAA-DfvkQ38Oj98YM75i2nQRQuQi3WUxbefN9rLu=ExeSsr+xfw at mail.
>> gmail.com>
>> Content-Type: text/plain; charset="utf-8"
>>
>> Please provide the input files for the supercell and the 2-atom unit cell.
>
>>
>> My guess is that by building your supercell you may not have follow the
>> same symmetry for 2-atom unit cell, if so then you will compensate
>> differente the total magnetic moment to a different value. QE seems to
>> assign the same pseudo potential for atoms in their simmetric position, if
>> I'm not wrong. So you may have a longer calculation by using supercell,
>> but
>> it should "assign" equivalently each atom. Unfortunately I have not come
>> across the QE code yet, but for my experience, it looks something like
>> this, possibly.
>>
>> Best Regards.
>
>
>> On 7 August 2017 at 12:13, Raji Abdulrafiu <tunderaji at gmail.com> wrote:
>>
>> >
>> > Dear Colleagues,
>> >
>> > Kindly help me to clarify the following: I was dealing with a system
>> which
>> > in its ground pristine state should have a magnetic moment of zero.
>> When  I
>> > performed both scf and relax  calculations of a simple 2-atom unit cell
>> of
>> > the system, the total/absolute magnetic moments was indeed zero.
>> However,
>> > on performing supercell scf/relax calculations (consisting of 128 atoms)
>> > for the same system, with the same pseudopotentials, while keeping all
>> the
>> > calculation parameters used for 2-atom unit cell constant for the
>> supercell
>> > (except for the k-points), the total (absolute) magnetization) are now
>> > ~10.49 (12.94) Bohr mag/cell. I had thought the magnetization should be
>> > zero, as obtained for the 2-atom cell. Could you please help to clarify
>> > this, perhaps, I am missing something?
>> >
>> > Thank you very much for your kind attention.
>> >
>> > AT Raji.
>> >
>> > ?*please note that I sent the same request earlier but got no response
>> up
>> > till now.?
>> >
>> >
>> > --
>> >
>> > ---------
>> >
>> >
>> >
>> > *Abdulrafiu Tunde RAJISchool of Interdisciplinary Research and Graduate
>> > Studies (SIRCGS), University of South Africa (UNISA),*
>> >
>> > *Mucklenuek,*
>> >
>> >
>> >
>> >
>> > *Pretoria 0003,South Africa.------------*
>> >
>> >
>> >
>> > --
>> >
>> > ---------
>> >
>> >
>> >
>> > *Abdulrafiu Tunde RAJI, PhD (Physics)School of Interdisciplinary
>> Research
>> > and Graduate Studies (SIRCGS), University of South Africa (UNISA),*
>> >
>> > *Mucklenuek,*
>> >
>>
>> >
>>
>>
>>
>> --
>> Ricardo Afonso
>> Student of Magnetism and Superconductivity Group
>> Federal University of Sao Carlos
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>
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-- 
Ricardo Afonso
Student of Magnetism and Superconductivity Group
Federal University of Sao Carlos
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