[Pw_forum] problem with degauss and magnetization
Ricardo Faccio
rfaccio at fq.edu.uy
Sun Mar 13 18:12:37 CET 2011
Hi
Magnetism due to vacancies in graphene can be seen understood following
the stoner criteria. It is a metallic system, with localized states at the
Fermi level, mainly due to non bonding states, that present to many peaks
at the Fermi level.
So, it is important to get a good DOS, mainly at the Fermi level. A big
degauss, smoothes the DOS, and thus affect the unbalance between Nup and
Ndn electrons.
For all of these reasons:
- try to reduce degauss, until having a converged results: energy and
total magnetic moment
- take care about the number of kpoints, since it has important effects in
the DOS, particularly at the Fermi level.
Regards
Ricardo
-------------------------------------------------
Dr. Ricardo Faccio
Prof. Adjunto de Física
Mail: Cryssmat-Lab., Cátedra de Física, DETEMA
Facultad de Química, Universidad de la República
Av. Gral. Flores 2124, C.C. 1157
C.P. 11800, Montevideo, Uruguay.
E-mail: rfaccio at fq.edu.uy
Phone: 598 2 924 98 59
598 2 929 06 48
Fax: 598 2 9241906
Web: http://cryssmat.fq.edu.uy/ricardo/ricardo.htm
> Dear Quantum Espresso users,
>
>
> I am trying to get the magnetization by creating one vacancy
> in 5x5 supercell of graphene.
> With different values of degauss the total magnetization is
> changing surprisingly. Is there anything wrong with my input ?.
> Could anybody please tell me some references where I
> can read detail about smearing and degauss ?.
>
>
> The total magnetization with different degauss are given as below,
>
> *degauss total magnetization
> 0.05 0.00
> 0.01 0.58
> 0.001 0.88
> 0.0001 0.88
>
> *
>
> I am posting my input file below.
>
>
>
> &CONTROL
> calculation = 'scf' ,
> restart_mode = 'from_scratch' ,
> outdir = 'OUT/',
> pseudo_dir = '/home/kaloni/pseudo/',
> prefix = 'g',
> tstress=.true.,
> /
> &SYSTEM
> ibrav = 4, a=12.199359575, b= 12.199359575,
> c=19.999668786, cosab= -0.5, cosac =0.0 , cosbc=0.0,
> nat= 49, ntyp= 1,
> ecutwfc = 40,
> ecutrho = 400,
> nspin =2, starting_magnetization = 1.0,
> occupations='smearing', smearing=' gaussian', degauss=0.05,
> nosym = .true.,
>
> /
> &ELECTRONS
> mixing_beta = 0.3
> conv_thr = 1.0d-9
> /
> ATOMIC_SPECIES
> C 12.0107 C.pz-rrkjus.UPF
> ATOMIC_POSITIONS (crystal)
> C -0.000437574 -0.000580938 0.000000015
> C 0.000878501 0.200420327 -0.000000008
> C 0.001210858 0.399950578 -0.000000071
> C -0.000312205 0.599509065 0.000000002
> C -0.000716730 0.798976722 0.000000025
> C 0.199479935 -0.000986699 -0.000000031
> C 0.200591611 0.200243356 0.000000020
> C 0.204951004 0.399348478 -0.000000039
> C 0.200756083 0.599210178 -0.000000027
> C 0.199615366 0.799016660 0.000000045
> C 0.399828248 -0.000558044 -0.000000011
> C 0.399613916 0.200154971 0.000000014
> C 0.401785094 0.599046302 -0.000000047
> C 0.400264884 0.799510584 0.000000019
> C 0.600023737 0.000445858 -0.000000037
> C 0.599500576 0.200387180 0.000000030
> C 0.594152084 0.399266958 0.000000290
> C 0.597008286 0.598889370 0.000000057
> C 0.600448742 0.800956977 -0.000000036
> C 0.800386518 0.000445469 -0.000000021
> C 0.800217273 0.200473648 -0.000000180
> C 0.798607049 0.399927530 0.000000120
> C 0.798270617 0.599140827 0.000000073
> C 0.799080030 0.799392409 -0.000000024
> C 0.132951308 0.065395469 0.000000019
> C 0.133142262 0.266027786 -0.000000014
> C 0.135800585 0.466331814 -0.000000062
> C 0.133194345 0.665806346 0.000000014
> C 0.132633945 0.865364014 0.000000018
> C 0.332386006 0.065362305 -0.000000012
> C 0.329787525 0.259493844 0.000000003
> C 0.336738546 0.468697263 -0.000000042
> C 0.333671463 0.665846245 -0.000000020
> C 0.333143624 0.865895587 0.000000044
> C 0.533078996 0.066642011 -0.000000019
> C 0.532824452 0.265959049 0.000000110
> C 0.531539380 0.468474465 0.000000226
> C 0.534652606 0.669416138 -0.000000013
> C 0.533415252 0.867317865 -0.000000015
> C 0.733533974 0.067101960 -0.000000071
> C 0.733185901 0.266889900 -0.000000007
> C 0.730336277 0.466262841 0.000000196
> C 0.731928945 0.665704201 0.000000020
> C 0.733842050 0.867300592 -0.000000017
> C 0.933534511 0.066657775 0.000000016
> C 0.933667182 0.266910925 -0.000000085
> C 0.933067875 0.466263286 0.000000000
> C 0.932454196 0.665766534 0.000000004
> C 0.932632612 0.865835315 0.000000008
> K_POINTS AUTOMATIC
> 4 4 1 1 1 1
>
>
> Thanks
>
> Thaneshwor Prashad Kaloni
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>
--
-------------------------------------------------
Dr. Ricardo Faccio
Prof. Adjunto de Física
Mail: Cryssmat-Lab., Cátedra de Física, DETEMA
Facultad de Química, Universidad de la República
Av. Gral. Flores 2124, C.C. 1157
C.P. 11800, Montevideo, Uruguay.
E-mail: rfaccio at fq.edu.uy
Phone: 598 2 924 98 59
598 2 929 06 48
Fax: 598 2 9241906
Web: http://cryssmat.fq.edu.uy/ricardo/ricardo.htm
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