Dar Tiagang,
I guess that the value 'celldm(3)= 10.431292329' should actually be
1.46419098375312488028, as it is interpreted as c/a, not simply c. If you
use the variables 'a' and 'c' in the input they are the absolute lengths
of the cell vectors and in Ångström. Just my guess...
Greetings from Paris,
apsi
-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
Ari Paavo Seitsonen / [email protected] / http://www.iki.fi/~apsi/
Ecole Normale Supérieure (ENS), Département de Chimie, Paris
Mobile (F) : +33 789 37 24 25 (CH) : +41 79 71 90 935
On Sat, 23 Mar 2019, Tiangang Zhou wrote:
Hello all,
I'm working on the beta-FeSe system. In the first step I have done a simple LDA
calculation. Unfortunately, after
adjusting ecutwfc and scf K_POINTS, I can’t get the relatively accurate result
compared to VASP and wien2k (the
result of VASP and wien2k agree well on the fermi surface). It’s likely that
the pseudopotential has some problem
or I miss some key steps. The input files are listed below.
fe_se.scf.in
```
&control
calculation = 'scf'
restart_mode='from_scratch',
prefix='fe_se',
pseudo_dir = '/home/tgzhou/softwares/qe_release_6.4/pseudo/',
outdir='tempdir/'
/
&system
ibrav= 6, celldm(1)= 7.124270293115536, celldm(3)= 10.431292329,
nat= 4, ntyp= 2,
ecutwfc = 120.0,
localization_thr = 0.01,
occupations='smearing', smearing='mp', degauss=0.02
/
&electrons
mixing_beta = 0.7,
conv_thr = 1.0d-10
/
ATOMIC_SPECIES
Fe 55.845 Fe.pz-n-kjpaw_psl.1.0.0.UPF
Se 78.96 Se.pz-n-kjpaw_psl.1.0.0.UPF
ATOMIC_POSITIONS crystal
Fe 0.000000000 0.000000000 0.000000000
Fe 0.500000000 0.500000000 0.000000000
Se 0.000000000 0.500000000 0.768115942
Se 0.500000000 0.000000000 0.231884057
K_POINTS automatic
8 8 4 0 0 0
```
fe_se.band.in
```
&control
calculation='bands'
pseudo_dir = '/home/tgzhou/softwares/qe_release_6.4/pseudo/',
outdir='tempdir/',
prefix='fe_se'
/
&system
ibrav= 6, celldm(1)= 7.124270293115536, celldm(3)= 10.431292329,
nat= 4, ntyp= 2,
ecutwfc = 120.0,
nbnd=20
/
&electrons
/
ATOMIC_SPECIES
Fe 55.845 Fe.pz-n-kjpaw_psl.1.0.0.UPF
Se 78.96 Se.pz-n-kjpaw_psl.1.0.0.UPF
ATOMIC_POSITIONS crystal
Fe 0.000000000 0.000000000 0.000000000
Fe 0.500000000 0.500000000 0.000000000
Se 0.000000000 0.500000000 0.768115942
Se 0.500000000 0.000000000 0.231884057
K_POINTS crystal_b
4
0.0 0.0 0.0 50
0.5 0.0 0.0 50
0.5 0.5 0.0 50
0.0 0.0 0.0 1
```
The band structure is in the path \Gamma-X-M-\Gamma. And those two have some
similarity but the qe FeSe band are
much more narrow.
qe FeSe band structure
https://drive.google.com/file/d/1wG1Nm-f5v03-kfefJoPZ4gSD4rYaJSQa/view
vasp FeSe band structure
https://drive.google.com/file/d/1T0iNg7oecpey2dD6BB9iNrvjS6rm7Mnr/view
Best,
Tiangang Zhou
School of Physics
Peking University
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