[Pw_forum] LO-TO splitting in complete phonon dispersion using PWSCF
Lorenzo Paulatto
lorenzo.paulatto at impmc.upmc.fr
Fri Nov 21 11:00:40 CET 2014
You can define a band as being LO or TO by continuity, but it won't
necessarily be Longitudinal or Transverse i nthe entire Brillouin zone.
In particular, from the [1/2 1/2 1/2] point I cannot say anything.
Especially since I do not know our cell geometry.
kind regards
On 20/11/14 17:43, Kondaiah Samudrala wrote:
> Dear Sir,
> Sorry for the eps figure. Now I attached new figure with pdf
> extension.... In the mean time, I am following the same definition for
> LO-TO splitting at Gamma point level. But, I am not clear about the
> below sentence far from Gamma.
>
>
> "An the end of the dynamical matrix file you have the frequencies and
> the atom displacements (3 times number of atoms complex numbers). If the
> displacement for every atom is parallel to the q-point, the mode is
> Longitudinal; if it is orthogonal, the mode is Transverse. In every
> other case it is neither. You can then associated the frequency with the
> label.".
>
> I would like to know that is there any possibility to know more details
> far from Gamma point. Here with I am adding the ip and ops of matdyn.x (
> Here I am using only one special point in the IBZ)
>
> *Matdyn.in :*
> &input
> asr='crystal',q_in_band_form=.true.
> fleig='matdyn.eig', fldyn='AB22.dyn',flfrc='AB2444_with_ASR.fc',
> flfrq='AB2_with_ASR.freq'
> /
> 1
> 0.5 0.5 0.5 2
>
> *AB2.dyn* :
> Dynamical Matrix in cartesian axes
>
> q = ( 0.500000000 0.500000000 0.500000000 )
>
> 1 1
> 0.03952920 0.00000000 -0.00374183 0.00000000 0.00000000
> 0.00000000
> -0.00374183 0.00000000 0.03952920 0.00000000 0.00000000
> 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 0.29542189
> 0.00000000
> 1 2
> 0.02007831 -0.00022229 -0.01131717 0.00672504 0.00000000
> 0.00000000
> -0.01131717 0.00672504 0.02007831 -0.00022229 0.00000000
> 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 -0.03673002
> 0.00282937
> 1 3
> -0.04191744 0.00000006 0.00162178 -0.00069950 0.00000000
> 0.00000000
> 0.00162178 -0.00069950 -0.04191744 0.00000006 0.00000000
> 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 -0.25545367
> -0.00387305
> 2 1
> 0.02007831 0.00022229 -0.01131717 -0.00672504 0.00000000
> 0.00000000
> -0.01131717 -0.00672504 0.02007831 0.00022229 0.00000000
> 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 -0.03673002
> -0.00282937
> 2 2
> 0.03952920 0.00000000 -0.00374183 0.00000000 0.00000000
> 0.00000000
> -0.00374183 0.00000000 0.03952920 0.00000000 0.00000000
> 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 0.29542189
> 0.00000000
> 2 3
> -0.04191744 -0.00000006 0.00162178 0.00069950 0.00000000
> 0.00000000
> 0.00162178 0.00069950 -0.04191744 -0.00000006 0.00000000
> 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 -0.25545367
> 0.00387305
> 3 1
> -0.04191744 -0.00000006 0.00162178 0.00069950 0.00000000
> 0.00000000
> 0.00162178 0.00069950 -0.04191744 -0.00000006 0.00000000
> 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 -0.25545367
> 0.00387305
> 3 2
> -0.04191744 0.00000006 0.00162178 -0.00069950 0.00000000
> 0.00000000
> 0.00162178 -0.00069950 -0.04191744 0.00000006 0.00000000
> 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 -0.25545367
> -0.00387305
> 3 3
> 0.10704556 0.00000000 -0.00739632 0.00000000 0.00000000
> 0.00000000
> -0.00739632 0.00000000 0.10704556 0.00000000 0.00000000
> 0.00000000
> 0.00000000 0.00000000 0.00000000 0.00000000 0.54383493
> 0.00000000
>
> *matdyn.modes:*
>
> diagonalizing the dynamical matrix ...
>
> q = 0.5000 0.5000 0.5000
> **************************************************************************
> freq ( 1) = 1.318544 [THz] = 43.981900 [cm-1]
> ( -0.411001 0.032309 -0.411001 0.032309 0.000000 0.000000 )
> ( -0.381067 -0.157332 -0.381067 -0.157332 0.000000 0.000000 )
> ( -0.395193 -0.062378 -0.395193 -0.062378 0.000000 0.000000 )
> freq ( 2) = 1.662161 [THz] = 55.443739 [cm-1]
> ( 0.000000 0.000000 0.000000 0.000000 0.578232 0.001810 )
> ( 0.000000 0.000000 0.000000 0.000000 0.578232 -0.001810 )
> ( 0.000000 0.000000 0.000000 0.000000 0.575577 0.000000 )
> freq ( 3) = 2.140009 [THz] = 71.383008 [cm-1]
> ( 0.249628 0.355541 -0.249628 -0.355541 0.000000 0.000000 )
> ( 0.274220 -0.336937 -0.274220 0.336937 0.000000 0.000000 )
> ( 0.349855 0.012425 -0.349855 -0.012425 0.000000 0.000000 )
> freq ( 4) = 2.763777 [THz] = 92.189664 [cm-1]
> ( -0.043052 0.489305 0.043052 -0.489305 0.000000 0.000000 )
> ( -0.032204 -0.490138 0.032204 0.490138 0.000000 0.000000 )
> ( -0.132110 -0.001463 0.132110 0.001463 0.000000 0.000000 )
> freq ( 5) = 4.043036 [THz] = 134.861157 [cm-1]
> ( -0.061283 0.494864 -0.061283 0.494864 0.000000 0.000000 )
> ( -0.060611 -0.494947 -0.060611 -0.494947 0.000000 0.000000 )
> ( 0.052041 0.000035 0.052041 0.000035 0.000000 0.000000 )
> freq ( 6) = 5.972075 [THz] = 199.206984 [cm-1]
> ( -0.480641 -0.101587 -0.480641 -0.101587 0.000000 0.000000 )
> ( -0.478284 0.112159 -0.478284 0.112159 0.000000 0.000000 )
> ( 0.131633 -0.001451 0.131633 -0.001451 0.000000 0.000000 )
> freq ( 7) = 7.226719 [THz] = 241.057396 [cm-1]
> ( -0.493843 0.042446 0.493843 -0.042446 0.000000 0.000000 )
> ( -0.492606 -0.054977 0.492606 0.054977 0.000000 0.000000 )
> ( 0.092914 0.001180 -0.092914 -0.001180 0.000000 0.000000 )
> freq ( 8) = 14.341371 [THz] = 478.376650 [cm-1]
> ( 0.000000 0.000000 0.000000 0.000000 -0.432733 0.552169 )
> ( 0.000000 0.000000 0.000000 0.000000 -0.432733 -0.552169 )
> ( 0.000000 0.000000 0.000000 0.000000 0.125310 0.000000 )
> freq ( 9) = 14.493257 [THz] = 483.443015 [cm-1]
> ( 0.000000 0.000000 0.000000 0.000000 -0.491770 -0.497872 )
> ( 0.000000 0.000000 0.000000 0.000000 -0.491770 0.497872 )
> ( 0.000000 0.000000 0.000000 0.000000 0.143430 0.000000 )
> **************************************************************************
>
> *AB2.freq*
>
> &plot nbnd= 9, nks= 1 /
> 0.500000 0.500000 0.500000
> 43.9819 55.4437 71.3830 92.1897 134.8612 199.2070
> 241.0574 478.3766 483.4430
>
> with regards
> S. Appalakondaiah
> PhD Schloar
> University of Hyderabad
>
>
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>
--
Dr. Lorenzo Paulatto
IdR @ IMPMC -- CNRS & Université Paris 6
phone: +33 (0)1 44275 084 / skype: paulatz
www: http://www-int.impmc.upmc.fr/~paulatto/
mail: 23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05
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