[Pw_forum] Defining an antiferromagnetic graphene nanoribbon

Axel Kohlmeyer akohlmey at cmm.chem.upenn.edu
Fri May 9 16:46:07 CEST 2008


On Fri, 9 May 2008, Roberto G. A. Veiga wrote:

RV> Hi, Adriano:

roberto,

RV> 3) It works.
RV> 

RV> I already ran this input, but I was not sure if the system (a narrow 
RV> graphene ribbon -- a chain -- with magnetic edges) had been defined 
RV> correctly.

well, to see if the system that you calculated is actually
what you thought it is, you could use the QE postprocessing
tools and dump the charge density and spin density and visualize it.
if they are where they should be and the location of the atoms
match what you expect, then you have a good chance that you 
made no serious error in the input...

cheers,
   axel.


RV> 
RV> Regards,
RV> 
RV> Roberto
RV> 
RV> Adriano.Mosca.Conte at roma2.infn.it wrote: It seems ok apart some details:
RV> 1) You have to define DIR.
RV> 2) The cell parameters with ibrav=8 have to be specified by:
RV>    celldm(1)=a,celldm(2)=b/a,celldm(3)=c/a
RV> 3) I'm not sure at 100% that the symbols "-" and "+" are allowed to
RV> specify atomic names.
RV> 
RV> > Dear PW users:
RV> >
RV> > I want to carry out a single point calculation of an antiferromagnetic
RV> > graphene nanoribbon with PWscf. Since such a system is magnetic, with a
RV> > specific magnetic orientation for the edge carbons, I have to perform a
RV> > spin-polarized calculation. I'd like to know if the following PW input is
RV> > suitable for such a calculation.
RV> >
RV> > &CONTROL
RV> >                    calculation = 'scf' ,
RV> >                   restart_mode = 'from_scratch' ,
RV> >                     pseudo_dir = '$DIR' ,
RV> >    /
RV> >    &SYSTEM
RV> >                          ibrav = 8,
RV> >                              A = 17.482046 ,
RV> >                              B = 20.000000 ,
RV> >                              C = 15.000000 ,
RV> >                            nat = 70 ,
RV> >                           ntyp = 4,
RV> >                        ecutwfc = 20.00 ,
RV> >                        ecutrho = 80.00 ,
RV> >                    occupations = 'smearing' ,
RV> >                        degauss = 0.01 ,
RV> >                       smearing = 'gaussian' ,
RV> >                          nspin = 2 ,
RV> >      starting_magnetization(1) = -1.0 ,
RV> >      starting_magnetization(2) =  1.0 ,
RV> >      starting_magnetization(3) =  0.0 ,
RV> >      starting_magnetization(4) =  0.0 ,
RV> >    /
RV> >    &ELECTRONS
RV> >                       conv_thr = 1.0D-6 ,
RV> >                    startingpot = 'atomic',
RV> >                    startingwfc = 'atomic',
RV> >                    mixing_mode = 'plain' ,
RV> >                    mixing_beta = 0.25 ,
RV> >                diagonalization = 'david' ,
RV> >   /
RV> >   ATOMIC_SPECIES
RV> >     C-1   12.0107  C.pbe.UPF
RV> >     C+1   12.0107  C.pbe.UPF
RV> >     C     12.0107  C.pbe.UPF
RV> >     H      1.0079  H.pbe.UPF
RV> >   ATOMIC_POSITIONS angstrom
RV> >   C+1       1.249543   -0.711074    0.000000
RV> >   C       0.000947   -0.016393   -0.000001
RV> >   C       0.000844    1.443145   -0.000001
RV> >   C       1.249381    2.159954    0.000001
RV> >   C       1.249409    3.608946    0.000001
RV> >   C       0.000843    4.325668   -0.000001
RV> >   C       0.000939    5.785283    0.000000
RV> >   C-1       1.249515    6.479991   -0.000001
RV> >   H       1.249981   -1.825631    0.000000
RV> >   H       1.249981    7.594413    0.000000
RV> >   C+1       3.746978   -0.711074    0.000000
RV> >   C       2.498382   -0.016393   -0.000001
RV> >   C       2.498279    1.443145   -0.000001
RV> >   C       3.746816    2.159954    0.000001
RV> >   C       3.746844    3.608946    0.000001
RV> >   C       2.498278    4.325668   -0.000001
RV> >   C       2.498374    5.785283    0.000000
RV> >   C-1       3.746950    6.479991   -0.000001
RV> >   H       3.747416   -1.825631    0.000000
RV> >   H       3.747416    7.594413    0.000000
RV> >   C+1       6.244413   -0.711074    0.000000
RV> >   C       4.995817   -0.016393   -0.000001
RV> >   C       4.995714    1.443145   -0.000001
RV> >   C       6.244251    2.159954    0.000001
RV> >   C       6.244279    3.608946    0.000001
RV> >   C       4.995713    4.325668   -0.000001
RV> >   C       4.995809    5.785283    0.000000
RV> >   C-1       6.244385    6.479991   -0.000001
RV> >   H       6.244851   -1.825631    0.000000
RV> >   H       6.244851    7.594413    0.000000
RV> >   C+1       8.741849   -0.711074    0.000000
RV> >   C       7.493253   -0.016393   -0.000001
RV> >   C       7.493150    1.443145   -0.000001
RV> >   C       8.741687    2.159954    0.000001
RV> >   C       8.741715    3.608946    0.000001
RV> >   C       7.493149    4.325668   -0.000001
RV> >   C       7.493245    5.785283    0.000000
RV> >   C-1       8.741821    6.479991   -0.000001
RV> >   H       8.742287   -1.825631    0.000000
RV> >   H       8.742287    7.594413    0.000000
RV> >   C+1      11.239284   -0.711074    0.000000
RV> >   C       9.990688   -0.016393   -0.000001
RV> >   C       9.990585    1.443145   -0.000001
RV> >   C      11.239122    2.159954    0.000001
RV> >   C      11.239150    3.608946    0.000001
RV> >   C       9.990584    4.325668   -0.000001
RV> >   C       9.990680    5.785283    0.000000
RV> >   C-1      11.239256    6.479991   -0.000001
RV> >   H      11.239722   -1.825631    0.000000
RV> >   H      11.239722    7.594413    0.000000
RV> >   C+1      13.736719   -0.711074    0.000000
RV> >   C      12.488123   -0.016393   -0.000001
RV> >   C      12.488020    1.443145   -0.000001
RV> >   C      13.736557    2.159954    0.000001
RV> >   C      13.736585    3.608946    0.000001
RV> >   C      12.488019    4.325668   -0.000001
RV> >   C      12.488115    5.785283    0.000000
RV> >   C-1      13.736691    6.479991   -0.000001
RV> >   H      13.737157   -1.825631    0.000000
RV> >   H      13.737157    7.594413    0.000000
RV> >   C+1      16.234154   -0.711074    0.000000
RV> >   C      14.985558   -0.016393   -0.000001
RV> >   C      14.985455    1.443145   -0.000001
RV> >   C      16.233992    2.159954    0.000001
RV> >   C      16.234020    3.608946    0.000001
RV> >   C      14.985454    4.325668   -0.000001
RV> >   C      14.985550    5.785283    0.000000
RV> >   C-1      16.234126    6.479991   -0.000001
RV> >   H      16.234592   -1.825631    0.000000
RV> >   H      16.234592    7.594413    0.000000
RV> >   K_POINTS  automatic
RV> >      2   1   1  0  0  0
RV> >
RV> > Regards,
RV> >
RV> > Roberto Veiga
RV> > PhD student
RV> > INSA-Lyon
RV> >
RV> >
RV> > ---------------------------------
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RV> > now._______________________________________________
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RV> >
RV> 
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RV> 
RV>        
RV> ---------------------------------
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-- 
=======================================================================
Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
   Center for Molecular Modeling   --   University of Pennsylvania
Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323
tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel: 1-215-898-5425
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