Si-DFPT + SO

[Jammi Tadaci]

Dear ELK users,

I'm trying to calculate a phonon dispersion of silicon.with spin-orbit:

tasks
  0
  205
  220

spinorb
 .true.

bfieldc
0.0  0.0  0.01

! scale the number of radial mesh points in the muffin-tins; this is so that
! gradients are accurately calculated
nrmtscf
  4

! limit the maximum number of self-consistent loops
maxscl
  30

! phonon q-point grid
ngridq
  4  4  4

! k-point grid should be commensurate with the q-point grid
ngridk
  4  4  4

avec
  5.13  5.13  0.00
  5.13  0.00  5.13
  0.00  5.13  5.13

scrpath
'scratch/'

sppath
'species/'

atoms
  1                                 : nspecies
  'Si.in'                           : spfname
  2                                 : natoms; atposl below
  0.0   0.0   0.0
  0.25  0.25  0.25

! These are the vertices to be joined for the phonon dispersion plot
plot1d
  7 200                                 : nvp1d, npp1d
  1.0   0.0   0.0
  0.5   0.5   0.0
  0.0   0.0   0.0
  0.5   0.0   0.0
  0.5   0.5   0.0
  0.5   0.25 -0.25
  0.5   0.0   0.0

After finish ground-state calulation I get error:

Info(elk): current task : 205

Error(phonon): spin-polarised phonons not yet available

Any help? I found some papers, where people calculated the dynamical matrices and electron-phonon
matrix elements with density functional perturbation theory with SO using ELK (or I am wrong?)

JImmi

[mfechner]

Dear Jimmi,

could you post the references to these papers? I would be very interested in this. In the meantime, the regular version of ELK has no DFPT for the spin-polarized system which consequently means no DFPT for computations with spin-orbit. The message you received from the code "Error(phonon): spin-polarised phonons not yet available." is a reflection on that.

best regards
Michael

[Markus]

Dear Jimmi,

use the supercell method instead, i.e. task 200. This will certainly work. Start with an LDA calculation, this is easier to converge.

Best regards,
Markus