using plot1d to plot 1D ELF profile

[Gang Tang]

Dear Users,

According to this tutorial https://sourceforge.net/p/elk/discussion/897820/thread/8c297bf308/, I use the following spacegroup.in file to generate the input file (elk.in).

 'Pm-3m'                               : hrmg
 12.1209679 12.1209679 12.1209679     : a, b, c
 90.0     90.0     90.0               : bc, ac, ab
 1  1  1                              : ncell
 .true.                               : primcell
 3                                    : nspecies
 'Cs'                                 : spsymb, spfname
 1                                    : nwpos
0.50000 0.50000 0.50000
'Pb'
 1
0.00000 0.00000 0.00000
 'I'
 1
0.50000 0.00000 0.00000

Following the examples (/elk-6.8.4/examples/ELF), and I use the following elk.in file to calculate the 1D ELF profile for CsPbI3 halide perovskite.

tasks
  0
  51

plot1d
  2  400
  0.0  0.0  0.0
  0.0  0.0  0.5

sppath
  './'

lradstp
  1

rgkmax
  11.0

gmaxvr
  22.0

msmooth
  4

lmaxapw
  12

lmaxo
  12

ngridk
 6 6 6

vkloff
  0.25  0.5  0.625

avec
12.12096790       0.000000000       0.000000000
0.000000000       12.12096790       0.000000000
0.000000000       0.000000000       12.12096790

atoms
   3                                    : nspecies
'Cs.in'                                 : spfname
1                                    : natoms; atposl, bfcmt below
 0.50000000    0.50000000    0.50000000    0.00000000  0.00000000  0.00000000
'Pb.in'                                 : spfname
1                                    : natoms; atposl, bfcmt below
 0.00000000    0.00000000    0.00000000    0.00000000  0.00000000  0.00000000
'I.in'                                  : spfname
3                                    : natoms; atposl, bfcmt below
 0.50000000    0.00000000    0.00000000    0.00000000  0.00000000  0.00000000
 0.00000000    0.50000000    0.00000000    0.00000000  0.00000000  0.00000000
 0.00000000    0.00000000    0.50000000    0.00000000  0.00000000  0.00000000

The calculated result is shown in the attachment, can anyone help me check my input file and is this result reliable? Thank you very much.

[Andrew Shyichuk]

Dear Gang,

I see two things here.

First, 1D/2D/3D plots correspond to geometry reported in GEOMETRY.OUT and INFO.OUT.
By default, Elk shifts the atoms so that the first one of the least abundant specie (i.e. a dopant) is at the origin. The shifts are reported in the stdout (.o) files.
I.e. when specifying geometry in elk.in, you must specify the plot lines for the geometry in INFO.OUT.

Second thing - there is a discontinuity (albeit slight) at about 3. I'd try making EOS (energy-volume) curves in the +-2% cell size range. If they are smooth enough. the basis is fine. If not, the basis must be tuned. Just make sure your RMTs do not change in the EOS series (consider setting them manually).

Otherwise it is a good input.

Best regards.
Andrew