[Pw_forum] graphene phonon dispersion

[yccheng.nju]

Why dont you show us your input file for matdyn.x ? I think it is due to
the wrong q-point setting.
On 15/06/11 12:28, yhho wrote:
> Dear all,
> I have tried many different way as I saw on pw_forum
> but I still can't get a good result which is similar to tthe figure
> from paper I found.
> In this figure, red line is what I got and gray line is from reference
> ref: *Physics Reports*
> <http://www.sciencedirect.com/science/journal/03701573>*Volume 409,
> Issue 2*
> <http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235540%232005%23995909997%23576885%23FLA%23&_cdi=5540&_pubType=J&view=c&_auth=y&_acct=C000053459&_version=1&_urlVersion=0&_userid=2446484&md5=88a06068733ddc56ccfa1fbe6299d583>*,
> March 2005, Pages 47-99*
> http://imageshack.us/photo/my-images/853/c2phdosvc1.jpg/
> I also found another paper shows a little different phonon dispersion
> figure of graphite:
> red line is my result and gray line is from reference
> ref: *10.1103/PhysRevLett.92.075501*
> http://imageshack.us/photo/my-images/851/c2phdosvc3.jpg/
> I have no idea to improve this
> because I have tried vc-relax and relax and the structure didn't
> change a lot due to that.
> And I also tried increasing q-points, there's no much different from
> the fewer q-points results.
> Please give me some suggestion. Thanks very much.
> *input file*
> *(scf.in)*
> &control
> calculation ='scf'
> restart_mode ='from_scratch'
> pseudo_dir ='/lustre/lwork/dyyang/bin/espresso-4.0.3/pseudo/'
> outdir ='./'
> prefix ='AuC'
> /
> &system
> ibrav =0
> celldm(1)= 4.6514
> nat = 2 ,
> ntyp = 1 ,
> ecutwfc = 24.0,
> ecutrho = 240.0,
> occupations ='smearing',
> degauss= 0.02
> /
> &electrons
> diagonalization= 'david'
> conv_thr = 1.0d-12
> mixing_beta = 0.7
> /
> ATOMIC_SPECIES
> C 12.0107 C.pz-rrkjus.UPF
> CELL_PARAMETERS (alat)
> 0.984533834 0.000000000 0.000000000
> -0.492266917 0.852631311 0.000000000
> 0.000000000 0.000000000 5.328569075
> ATOMIC_POSITIONS {crystal}
> C 0.481112321 1.128944752 0.517391300
> C 0.814471461 0.795556146 0.517391309
> K_POINTS
> 7
> 0.0000000 0.0000000 0.0000000 0.1250000
> 0.0000000 0.2932100 0.0000000 0.2500000
> 0.0000000 -0.5864199 0.0000000 0.1250000
> 0.2539273 0.1466050 0.0000000 0.5000000
> 0.2539273 0.4398150 0.0000000 0.5000000
> -0.5078546 -0.2932100 0.0000000 0.2500000
> -0.5078546 0.0000000 0.0000000 0.2500000
> (*ph.in*)
> phonons of AuC
> &inputph
> tr2_ph=1.0d-12,
> ldisp=.true.,
> nq1=4, nq2=4, nq3=1
> amass(1)= 12.0107
> prefix='AuC',
> outdir='./'
> fildyn='AuC.dyn',
> /
> --
> Yu-Han Ho
> Research Assistant
> Institute of Atomic and Molecular Sciences(IAMS), lab503
> No. 1, Roosevelt Rd., Sec. 4, Taipei, 10617, Taiwan
> Tel: 886-2-2362-0212
>
>
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