[Pw_forum] Defining an antiferromagnetic graphene nanoribbon
Roberto G. A. Veiga
raveiga at yahoo.com
Fri May 9 17:07:23 CEST 2008
Hi, Adriano:
1) It is defined. This input was extracted from a shell script I use to run PW.
2) Is it mandatory? PW ran without any warning, though.
What I wanted is to define a chain, that is, it is periodic only along x direction. y and z are just large enough to prevent spurious interactions with the ribbon images. Is there another (better) way to specify the cell parameters for such a system?
3) It works.
I already ran this input, but I was not sure if the system (a narrow graphene ribbon -- a chain -- with magnetic edges) had been defined correctly.
Regards,
Roberto
Adriano.Mosca.Conte at roma2.infn.it wrote: 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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