Re: [Phonopy-users] Phonon dispersion of Si[001] direction

[Atz T. <atz...@gm...>]

Hi,

I guess your q-path is not well chosen. If you want to set X
direction, it is [0.5, 0.5, 0] in phonopy.

Togo

2010/6/28 Xiaoliang Zhang <zha...@ie...>:
> Why can't I get good result for phonon dispersion of Si[001] direction?
> The following is what I do,
> First, I prepare
>
> INPHON:
>
> ATOM_NAME = Si
> NDIM =  2 2 2
> LSUPER = .TRUE.
> ND = 1
> NPOINTS = 1000
> QI = 0.0 0.0 0.0
> QF = 0.0 0.0 1.0
>
> and
>
> POSCAR:
> Si
> 5.43
> 0.5 0.5 0.0
> 0.0 0.5 0.5
> 0.5 0.0 0.5
> 2
> Direct
> 0.0000000000000 0.00000000000 0.0000000000000
> 0.2500000000000 0.25000000000 0.2500000000000
>
> and then,
> [dwtang@LB270107 ~/phonopy/work/si]$ phonopy
>
> then I obtain
> SPOSCAR
> Si
>  1.0000000000000000
>      5.4299999999999997    5.4299999999999997    0.0000000000000000
>      0.0000000000000000    5.4299999999999997    5.4299999999999997
>      5.4299999999999997    0.0000000000000000    5.4299999999999997
>   16
> Direct
>   0.0000000000000000  0.0000000000000000  0.0000000000000000
>   0.5000000000000000  0.0000000000000000  0.0000000000000000
>   0.0000000000000000  0.5000000000000000  0.0000000000000000
>   0.5000000000000000  0.5000000000000000  0.0000000000000000
>   0.0000000000000000  0.0000000000000000  0.5000000000000000
>   0.5000000000000000  0.0000000000000000  0.5000000000000000
>   0.0000000000000000  0.5000000000000000  0.5000000000000000
>   0.5000000000000000  0.5000000000000000  0.5000000000000000
>   0.1250000000000000  0.1250000000000000  0.1250000000000000
>   0.6250000000000000  0.1250000000000000  0.1250000000000000
>   0.1250000000000000  0.6250000000000000  0.1250000000000000
>   0.6250000000000000  0.6250000000000000  0.1250000000000000
>   0.1250000000000000  0.1250000000000000  0.6250000000000000
>   0.6250000000000000  0.1250000000000000  0.6250000000000000
>   0.1250000000000000  0.6250000000000000  0.6250000000000000
>   0.6250000000000000  0.6250000000000000  0.6250000000000000
> and
> POSCAR-001
> Si
>  1.0000000000000000
>      5.4299999999999997    5.4299999999999997    0.0000000000000000
>      0.0000000000000000    5.4299999999999997    5.4299999999999997
>      5.4299999999999997    0.0000000000000000    5.4299999999999997
>   16
> Direct
>   0.0013022224331244  0.0000000000000000  0.0000000000000000
>   0.5000000000000000  0.0000000000000000  0.0000000000000000
>   0.0000000000000000  0.5000000000000000  0.0000000000000000
>   0.5000000000000000  0.5000000000000000  0.0000000000000000
>   0.0000000000000000  0.0000000000000000  0.5000000000000000
>   0.5000000000000000  0.0000000000000000  0.5000000000000000
>   0.0000000000000000  0.5000000000000000  0.5000000000000000
>   0.5000000000000000  0.5000000000000000  0.5000000000000000
>   0.1250000000000000  0.1250000000000000  0.1250000000000000
>   0.6250000000000000  0.1250000000000000  0.1250000000000000
>   0.1250000000000000  0.6250000000000000  0.1250000000000000
>   0.6250000000000000  0.6250000000000000  0.1250000000000000
>   0.1250000000000000  0.1250000000000000  0.6250000000000000
>   0.6250000000000000  0.1250000000000000  0.6250000000000000
>   0.1250000000000000  0.6250000000000000  0.6250000000000000
>   0.6250000000000000  0.6250000000000000  0.6250000000000000
> then
> I use pwscf software to compute force, and got file
> FORCE
> 1
> 1  0.0013022224331244  0.0000000000000000  0.0000000000000000
>      -0.093268087606915     -0.093268087606915     -0.001578915041816
>       0.006596681847888      0.006596681847888     -0.000052193413693
>      -0.006085289237862      0.003157315862808      0.003559179437203
>       0.003145488783843     -0.006067548619414     -0.003403884748185
>       0.003157315862808     -0.006085289237862      0.003559179437203
>      -0.006067548619414      0.003145488783843     -0.003403884748185
>      -0.000335271977614     -0.000335271977614     -0.000058621174000
>       0.000878289168351      0.000878289168351     -0.000055792959465
>       0.039713531391302      0.039713531391302      0.031223231356966
>       0.038737026045459      0.038737026045459     -0.030079861353553
>       0.008524752829582      0.008673105537468      0.000179463067772
>      -0.001857365618316     -0.001860708053676      0.000051936303281
>       0.008673105537468      0.008524752829582      0.000179463067772
>      -0.001860708053676     -0.001857365618316      0.000051936303281
>       0.000020054612158      0.000020054612158     -0.001943240496018
>       0.000027767924526      0.000027767924526      0.001772262071851
> and then
> I modify the INPHON to be
> ATOM_NAME = Si
> NDIM =  2 2 2
> LSUPER = .false.
> ND = 1
> NPOINTS = 1000
> QI = 0.0 0.0 0.0
> QF = 0.0 0.0 1.0
>
> and then
> [dwtang@LB270107 ~/phonopy/work/si]$ phonopy -p -s
>
> So I get the phonon dispersion of Si along [0 0 0] direction, but why is it
> so strange?
>
> phonopy.jpg is what form phonopy as above.
> sw.jpg is from SW potential, which is so different form phonopy's result.
>
>
>
>
> ------------------------------------------------------------------------------
> This SF.net email is sponsored by Sprint
> What will you do first with EVO, the first 4G phone?
> Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first
> _______________________________________________
> Phonopy-users mailing list
> Pho...@li...
> https://lists.sourceforge.net/lists/listinfo/phonopy-users
>
>



-- 
Atsushi Togo
http://atztogo.users.sourceforge.net/
atz...@gm...