[Pw_forum] Defining an antiferromagnetic graphene nanoribbon

[Adriano.Mosca.Conte at roma2.infn.it]

It seems ok apart some details:
1) You have to define DIR.
2) The cell parameters with ibrav=8 have to be specified by:
   celldm(1)=a,celldm(2)=b/a,celldm(3)=c/a
3) I'm not sure at 100% that the symbols "-" and "+" are allowed to
specify atomic names.

> Dear PW users:
>
> I want to carry out a single point calculation of an antiferromagnetic
> graphene nanoribbon with PWscf. Since such a system is magnetic, with a
> specific magnetic orientation for the edge carbons, I have to perform a
> spin-polarized calculation. I'd like to know if the following PW input is
> suitable for such a calculation.
>
> &CONTROL
>                    calculation = 'scf' ,
>                   restart_mode = 'from_scratch' ,
>                     pseudo_dir = '$DIR' ,
>    /
>    &SYSTEM
>                          ibrav = 8,
>                              A = 17.482046 ,
>                              B = 20.000000 ,
>                              C = 15.000000 ,
>                            nat = 70 ,
>                           ntyp = 4,
>                        ecutwfc = 20.00 ,
>                        ecutrho = 80.00 ,
>                    occupations = 'smearing' ,
>                        degauss = 0.01 ,
>                       smearing = 'gaussian' ,
>                          nspin = 2 ,
>      starting_magnetization(1) = -1.0 ,
>      starting_magnetization(2) =  1.0 ,
>      starting_magnetization(3) =  0.0 ,
>      starting_magnetization(4) =  0.0 ,
>    /
>    &ELECTRONS
>                       conv_thr = 1.0D-6 ,
>                    startingpot = 'atomic',
>                    startingwfc = 'atomic',
>                    mixing_mode = 'plain' ,
>                    mixing_beta = 0.25 ,
>                diagonalization = 'david' ,
>   /
>   ATOMIC_SPECIES
>     C-1   12.0107  C.pbe.UPF
>     C+1   12.0107  C.pbe.UPF
>     C     12.0107  C.pbe.UPF
>     H      1.0079  H.pbe.UPF
>   ATOMIC_POSITIONS angstrom
>   C+1       1.249543   -0.711074    0.000000
>   C       0.000947   -0.016393   -0.000001
>   C       0.000844    1.443145   -0.000001
>   C       1.249381    2.159954    0.000001
>   C       1.249409    3.608946    0.000001
>   C       0.000843    4.325668   -0.000001
>   C       0.000939    5.785283    0.000000
>   C-1       1.249515    6.479991   -0.000001
>   H       1.249981   -1.825631    0.000000
>   H       1.249981    7.594413    0.000000
>   C+1       3.746978   -0.711074    0.000000
>   C       2.498382   -0.016393   -0.000001
>   C       2.498279    1.443145   -0.000001
>   C       3.746816    2.159954    0.000001
>   C       3.746844    3.608946    0.000001
>   C       2.498278    4.325668   -0.000001
>   C       2.498374    5.785283    0.000000
>   C-1       3.746950    6.479991   -0.000001
>   H       3.747416   -1.825631    0.000000
>   H       3.747416    7.594413    0.000000
>   C+1       6.244413   -0.711074    0.000000
>   C       4.995817   -0.016393   -0.000001
>   C       4.995714    1.443145   -0.000001
>   C       6.244251    2.159954    0.000001
>   C       6.244279    3.608946    0.000001
>   C       4.995713    4.325668   -0.000001
>   C       4.995809    5.785283    0.000000
>   C-1       6.244385    6.479991   -0.000001
>   H       6.244851   -1.825631    0.000000
>   H       6.244851    7.594413    0.000000
>   C+1       8.741849   -0.711074    0.000000
>   C       7.493253   -0.016393   -0.000001
>   C       7.493150    1.443145   -0.000001
>   C       8.741687    2.159954    0.000001
>   C       8.741715    3.608946    0.000001
>   C       7.493149    4.325668   -0.000001
>   C       7.493245    5.785283    0.000000
>   C-1       8.741821    6.479991   -0.000001
>   H       8.742287   -1.825631    0.000000
>   H       8.742287    7.594413    0.000000
>   C+1      11.239284   -0.711074    0.000000
>   C       9.990688   -0.016393   -0.000001
>   C       9.990585    1.443145   -0.000001
>   C      11.239122    2.159954    0.000001
>   C      11.239150    3.608946    0.000001
>   C       9.990584    4.325668   -0.000001
>   C       9.990680    5.785283    0.000000
>   C-1      11.239256    6.479991   -0.000001
>   H      11.239722   -1.825631    0.000000
>   H      11.239722    7.594413    0.000000
>   C+1      13.736719   -0.711074    0.000000
>   C      12.488123   -0.016393   -0.000001
>   C      12.488020    1.443145   -0.000001
>   C      13.736557    2.159954    0.000001
>   C      13.736585    3.608946    0.000001
>   C      12.488019    4.325668   -0.000001
>   C      12.488115    5.785283    0.000000
>   C-1      13.736691    6.479991   -0.000001
>   H      13.737157   -1.825631    0.000000
>   H      13.737157    7.594413    0.000000
>   C+1      16.234154   -0.711074    0.000000
>   C      14.985558   -0.016393   -0.000001
>   C      14.985455    1.443145   -0.000001
>   C      16.233992    2.159954    0.000001
>   C      16.234020    3.608946    0.000001
>   C      14.985454    4.325668   -0.000001
>   C      14.985550    5.785283    0.000000
>   C-1      16.234126    6.479991   -0.000001
>   H      16.234592   -1.825631    0.000000
>   H      16.234592    7.594413    0.000000
>   K_POINTS  automatic
>      2   1   1  0  0  0
>
> Regards,
>
> Roberto Veiga
> PhD student
> INSA-Lyon
>
>
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