[Pw_forum] high symmetric Points

[Ari P Seitsonen]

Dear Nh Ben,

   Could this be due to different units for the k points? For example 
'crystal' versus '2pi/a', as the second point looks like (-1/3,2/3) above 
but contains apparently the 1/sqrt(3) ~= 0.57735... in the generated k 
points.

   Just guessing... Sorry if I'm wrong. :)

     Greetings from Zurich,

        apsi

-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
   Ari Paavo Seitsonen / Ari.P.Seitsonen at iki.fi / http://www.iki.fi/~apsi/
   Institut für Chemie der Universität Zürich, CH-8057 Zürich
   Tel: +41 44 63 54 497  /  Mobile: +41 79 71 90 935


On Thu, 1 May 2014, BENYAHIA NEZHA wrote:

> Dear Quantum esspresso members
> 
> I'am calculating the phonons frequencies of the InAs in the wurtzite
> structure, when i plotted its dispersion curve it seems wrong, then i tried 
> with Plotphon in the Quantum esspresso package using of course my InAs.fc &
> InAs.freq.gp. The resulting dispersion curve was right when compared with
> another curves, and finally i undersand that the problem was on the k-points
> which were different from those that i took in my first calculation.
> I took these hight symmetric direction Γ K M Γ A L with there coordinates
> (as mensionned in the plotphon package)
> 1   0.000000000  0.000000000  0.000000000  G
> 50 -0.333333333  0.666666667  0.000000000  K
> 50  0.000000000  0.500000000  0.000000000  M
> 50  0.000000000  0.000000000  0.000000000  G
> 50  0.000000000  0.000000000  0.500000000  A
> 50  0.000000000  0.500000000  0.500000000  L
> and i put them in the xcrysden to generate Kpoints, but unfortunately, it
> gave me a list of kpoints different from those generated by plotphon. I dont
> understand why? 
> My other question is:
> Is there some method to extract the high symmetric directions  from a given
> Klist. I know how to do   "high symmetric
> directions"...................>"Klist" using crysden but not the opposite.
> For exemple what are the high symmetric directions of this Klist (this was
> generated with QE plotphon package in the examples):
>   251
>    0.00000   0.00000   0.00000  1.00
>   -0.00667   0.01155   0.00000  1.00
>   -0.01333   0.02309   0.00000  1.00
>   -0.02000   0.03464   0.00000  1.00
>   -0.02667   0.04619   0.00000  1.00
>   -0.03333   0.05774   0.00000  1.00
>   -0.04000   0.06928   0.00000  1.00
>   -0.04667   0.08083   0.00000  1.00
>   -0.05333   0.09238   0.00000  1.00
>   -0.06000   0.10392   0.00000  1.00
>   -0.06667   0.11547   0.00000  1.00
>   -0.07333   0.12702   0.00000  1.00
>   -0.08000   0.13856   0.00000  1.00
>   -0.08667   0.15011   0.00000  1.00
>   -0.09333   0.16166   0.00000  1.00
>   -0.10000   0.17321   0.00000  1.00
>   -0.10667   0.18475   0.00000  1.00
>   -0.11333   0.19630   0.00000  1.00
>   -0.12000   0.20785   0.00000  1.00
>   -0.12667   0.21939   0.00000  1.00
>   -0.13333   0.23094   0.00000  1.00
>   -0.14000   0.24249   0.00000  1.00
>   -0.14667   0.25403   0.00000  1.00
>   -0.15333   0.26558   0.00000  1.00
>   -0.16000   0.27713   0.00000  1.00
>   -0.16667   0.28868   0.00000  1.00
>   -0.17333   0.30022   0.00000  1.00
>   -0.18000   0.31177   0.00000  1.00
>   -0.18667   0.32332   0.00000  1.00
>   -0.19333   0.33486   0.00000  1.00
>   -0.20000   0.34641   0.00000  1.00
>   -0.20667   0.35796   0.00000  1.00
>   -0.21333   0.36950   0.00000  1.00
>   -0.22000   0.38105   0.00000  1.00
>   -0.22667   0.39260   0.00000  1.00
> -0.23333   0.40415   0.00000  1.00
>   -0.24000   0.41569   0.00000  1.00
>   -0.24667   0.42724   0.00000  1.00
>   -0.25333   0.43879   0.00000  1.00
>   -0.26000   0.45033   0.00000  1.00
>   -0.26667   0.46188   0.00000  1.00
>   -0.27333   0.47343   0.00000  1.00
>   -0.28000   0.48497   0.00000  1.00
>   -0.28667   0.49652   0.00000  1.00
>   -0.29333   0.50807   0.00000  1.00
>   -0.30000   0.51962   0.00000  1.00
>   -0.30667   0.53116   0.00000  1.00
>   -0.31333   0.54271   0.00000  1.00
>   -0.32000   0.55426   0.00000  1.00
>   -0.32667   0.56580   0.00000  1.00
>   -0.33333   0.57735   0.00000  1.00
>   -0.32667   0.57735   0.00000  1.00
>   -0.32000   0.57735   0.00000  1.00
>   -0.31333   0.57735   0.00000  1.00
>   -0.30667   0.57735   0.00000  1.00
>   -0.30000   0.57735   0.00000  1.00
>   -0.29333   0.57735   0.00000  1.00
>   -0.28667   0.57735   0.00000  1.00
>   -0.28000   0.57735   0.00000  1.00
>   -0.27333   0.57735   0.00000  1.00
>   -0.26667   0.57735   0.00000  1.00
>   -0.26000   0.57735   0.00000  1.00
>   -0.25333   0.57735   0.00000  1.00
>   -0.24667   0.57735   0.00000  1.00
>   -0.24000   0.57735   0.00000  1.00
>   -0.23333   0.57735   0.00000  1.00
>   -0.22667   0.57735   0.00000  1.00
>   -0.22000   0.57735   0.00000  1.00
>   -0.21333   0.57735   0.00000  1.00
> .........................................................
> 
> I'll be very  gratefull if you help me!!!!!!!!!!
> 
> 
> 
> 
> 
> Regards
> 
> Nh Ben
> 
>