[Pw_forum] how to calculate carbon nanorribon with AFM ordering

[Giovanni Cantele]

On Nov 27, 2013, at 2:34 PM, José Gadelha da Silva Filho <gadelha at fisica.ufc.br> wrote:

> Dear Giovanni,
> 
> I did the calculation with the input file that you used. The band structure is perfect but the Density of states still wrong!
> I supposed to see a split at the Fermi energy with a peak for spin up from a dispersive level and other down from other dispersive level. However ther DOS for spin-up and sin-down is the same. I belive this result is wrong! Do you agree?


no, because this is what happens if you look for the FM solution. The AFM state corresponds to perfect symmetry between the two edges. Indeed, if you try to plot the spin-up and spin-dw
band structures they should perfectly overlap, which agrees with your DOS.
A quick literature search should give you hundreds of results on the subject.

Giovanni

> 
> Can you look for the result, please?
> 
> https://docs.google.com/a/fisica.ufc.br/file/d/0B-4bqg57O9pKYTVBU2dQYUdobkk/edit
> 
> 
> 
> 
> 2013/11/27 José Gadelha da Silva Filho <gadelha at fisica.ufc.br>
> Dear Giovanni,
> 
> Before write to you I did the calculation following the descriptions on the website
> 
> http://qe-forge.org/pipermail/pw_forum/2011-May/094823.html
> 
> or in 
> 
> http://blog.sina.com.cn/s/blog_5f15ead20100drss.html
> 
> In any case it's not correct. I not found the AF magnetization.
> 
> Now I did exactly what you said however I continue found a mistake. 
> 
> I don't understand why my initial guess don't converge for correct spin up and down. Please look for the figure that I attached. 
> 
> Thanks a lot
> 
> 
> 
> 2013/11/25 José Gadelha da Silva Filho <gadelha at fisica.ufc.br>
> I tried  to calculate DOS for  graphene nanoribbon  with antiferromagnetic (AFM) configuration. I used  QE  4.1.2, QE 5.0 and QE 5.0.2.  Unfortunately I always take a FM ordering.  I would like to know what is wrong in my input data:
> 
> 
> &control
> calculation = 'scf' ,
> outdir = 'fita' ,
> pseudo_dir = 'pseudo' ,
> prefix = 'fita' ,
> verbosity = 'high' ,
> wf_collect=.true.,
> /
> &system
> ibrav=0,
> nat = 10,
> ntyp = 4,
> ecutwfc = 93 ,
> nbnd = 60,
> occupations = 'smearing' ,
> degauss = 0.008 ,
> nspin = 2, 
> starting_magnetization(1) = 1.0,
> starting_magnetization(2) = -1.0,
> starting_magnetization(3) = 1.0,
> starting_magnetization(4) = -1.0,
> /
> &electrons
> diagonalization='david',
> mixing_mode = 'plain',
> mixing_beta = 0.7,
> conv_thr =  1.0d-6,
> /
> ATOMIC_SPECIES
>  H1  1.007940  H.pw-mt_fhi.UPF 
>  C1  12.010700 C.pw-mt_fhi.UPF
>  C2 12.010700 C.pw-mt_fhi.UPF
>  H2 1.007940  H.pw-mt_fhi.UPF
> ATOMIC_POSITIONS crystal
>  H1 0.987129 0.348775 0.499998
>  C1 0.987081 0.389095 0.500002
>  C2 0.487078 0.413829 0.500002
>  C1 0.486874 0.466305 0.500002
>  C2 0.986871 0.491858 0.499998
>  C1 0.986838 0.543986 0.500002
>  C2 0.486787 0.569538 0.500002
>  C1 0.486868 0.622014 0.500002
>  C2 0.986868 0.646743 0.500002
>  H2 0.986685 0.687058 0.499998
> CELL_PARAMETERS bohr
> 4.705211 0.000000 0.000000
> 0.000000 52.410382 0.000000
> 0.000000 0.000000 16.588710
> 
> 
> K_POINTS automatic
> 15 1 1 0 0 0 
> 
> 
> 2013/11/25 José Gadelha da Silva Filho <gadelha at fisica.ufc.br>
>  I tried  to calculate DOS for  graphene nanoribbon  with antiferromagnetic (AFM) configuration. I used  QE  4.1.2, QE 5.0 and QE 5.0.2.  Unfortunately I always take a FM ordering.  I would like to know what is wrong in my input data:
> 
> -- 
> José Gadelha da Silva Filho
> 
> Aluno de Doutorado do Curso de Pós-Graduação em Física
> da Universidade Federal do Ceará.
> 
> 
> 
> -- 
> José Gadelha da Silva Filho
> 
> Aluno de Doutorado do Curso de Pós-Graduação em Física
> da Universidade Federal do Ceará.
> 
> 
> 
> -- 
> José Gadelha da Silva Filho
> 
> Aluno de Doutorado do Curso de Pós-Graduação em Física
> da Universidade Federal do Ceará.
> 
> 
> 
> -- 
> José Gadelha da Silva Filho
> 
> Aluno de Doutorado do Curso de Pós-Graduação em Física
> da Universidade Federal do Ceará.
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--

Giovanni Cantele, PhD
CNR-SPIN
c/o Dipartimento di Scienze Fisiche
Universita' di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy
e-mail: giovanni.cantele at spin.cnr.it
Phone: +39 081 676910
Skype contact: giocan74

ResearcherID: http://www.researcherid.com/rid/A-1951-2009
Web page: http://people.na.infn.it/~cantele
                     http://www.nanomat.unina.it

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