[Pw_forum] Problem with band structure computation
jchuang
jchuang at pub.iams.sinica.edu.tw
Tue Aug 30 08:57:14 CEST 2011
Dear all,
I've got a problem when computing the band structure for mono-layer CaC6.
The paper I followed is here (Arxiv preprint arXiv:1105.3736, 2011 -
arxiv.org).
They got their results from QE, too.
The problem is not about QE running process. It's about the result I got
from QE simulation.
If I set the parameters (atomic positions and celldm) as the same as paper.
The band structure I got was different from paper.
Some bands are fine, but some are distorted.
For example, part of a band with flat shape be tilted.
The link for my result is here. (http://imgur.com/fUSna)
It looks like something wrong with my atomic structure.
But it isn't. I had examined the atomic structure and k-path for many times.
To check the validity of atomic positions. I also tried the same structure
with VASP.
The result from VASP could fit the paper pretty well.
To check the validity of input files for QE. (parameters and k-path)
I tried to plot the band structure of mono-layer LiC6 with QE.
The band structure of LiC6 could fit the paper, too.
I had tried to relax the structure or use other pseudo potential files, but
still none better.
Why I use the correct structure and correct input files, but couldn't get a
correct result?
Have there been any wrong in my input setting?
Could someone please give me any advices or clues?
Any suggestions will be greatly appreciated.
Best regards,
J. C. Huang IAMS, Taiwan
================= the following is my input files =================
Scf.in
&control
calculation ='scf'
restart_mode ='from_scratch'
pseudo_dir ='/lustre/lwork/dyyang/bin/espresso-4.0.3/pseudo/'
outdir ='./'
prefix ='AuC'
disk_io='low',
wf_collect=.TRUE.,
/
&system
ibrav = 4,
celldm(1) = 8.050232711,
celldm(3) = 4.694835681,
nat = 7,
ntyp = 2,
ecutwfc = 45,
ecutrho = 400,
occupations = "smearing",
smearing = 'gaussian'
degauss = 0.002D0
/
&electrons
diagonalization='david'
mixing_mode = 'plain'
conv_thr = 1.0e-08
mixing_beta = 0.7
/
&ions
bfgs_ndim = 3,
ATOMIC_SPECIES
Ca 40.08 Ca.pz-n-vbc.UPF
C 12.0107 C.pz-vbc.UPF
ATOMIC_POSITIONS {crystal}
Ca 0.66667 0.33333 0.61200
C 0.33333 0.00000 0.50000
C 0.33333 0.33333 0.50000
C 0.00000 0.33333 0.50000
C 0.00000 0.66667 0.50000
C 0.66667 0.66667 0.50000
C 0.66667 0.00000 0.50000
K_POINTS (automatic)
16 16 1 0 0 0
Band1.in
# self-consistent calculation
&control
calculation='bands',
restart_mode='from_scratch',
prefix='AuC',
pseudo_dir = '/lustre/lwork/dyyang/bin/espresso-4.0.3/pseudo/',
outdir='./'
tstress = .true.
tprnfor = .true.
forc_conv_thr = 1.0e-3
/
&system
ibrav = 4,
celldm(1) = 8.050232711,
celldm(3) = 4.694835681,
nat=7, ntyp=2
ecutwfc =45.0,
ecutrho =400,
occupations = "smearing",
smearing = "gaussian",
degauss = 0.002D0,
nbnd= 20
/
&electrons
diagonalization='david'
mixing_mode = 'plain'
mixing_beta = 0.7
conv_thr = 1.0e-8
/
&ions
bfgs_ndim = 3,
ATOMIC_SPECIES
Ca 40.08 Ca.pz-n-vbc.UPF
C 12.0107 C.pz-vbc.UPF
ATOMIC_POSITIONS {crystal}
Ca 0.66667 0.33333 0.61200
C 0.33333 0.00000 0.50000
C 0.33333 0.33333 0.50000
C 0.00000 0.33333 0.50000
C 0.00000 0.66667 0.50000
C 0.66667 0.66667 0.50000
C 0.66667 0.00000 0.50000
K_POINTS {crystal}
49
0.00000000 0.00000000 0.00000000 1
0.03125000 0.00000000 0.00000000 2
0.06250000 0.00000000 0.00000000 3
0.09375000 0.00000000 0.00000000 4
0.12500000 0.00000000 0.00000000 5
0.15625000 0.00000000 0.00000000 6
0.18750000 0.00000000 0.00000000 7
0.21875000 0.00000000 0.00000000 8
0.25000000 0.00000000 0.00000000 9
0.28125000 0.00000000 0.00000000 10
0.31250000 0.00000000 0.00000000 11
0.34375000 0.00000000 0.00000000 12
0.37500000 0.00000000 0.00000000 13
0.40625000 0.00000000 0.00000000 14
0.43750000 0.00000000 0.00000000 15
0.46875000 0.00000000 0.00000000 16
0.50000000 0.00000000 0.00000000 17
0.48958333 0.02083333 0.00000000 18
0.47916666 0.04166666 0.00000000 19
0.46874999 0.06249999 0.00000000 20
0.45833333 0.08333332 0.00000000 21
0.44791666 0.10416666 0.00000000 22
0.43749999 0.12499999 0.00000000 23
0.42708332 0.14583332 0.00000000 24
0.41666665 0.16666665 0.00000000 25
0.40624998 0.18749998 0.00000000 26
0.39583331 0.20833331 0.00000000 27
0.38541664 0.22916664 0.00000000 28
0.37499997 0.24999997 0.00000000 29
0.36458331 0.27083331 0.00000000 30
0.35416664 0.29166664 0.00000000 31
0.34374997 0.31249997 0.00000000 32
0.33333330 0.33333330 0.00000000 33
0.31249997 0.31249997 0.00000000 34
0.29166664 0.29166664 0.00000000 35
0.27083331 0.27083331 0.00000000 36
0.24999997 0.24999997 0.00000000 37
0.22916664 0.22916664 0.00000000 38
0.20833331 0.20833331 0.00000000 39
0.18749998 0.18749998 0.00000000 40
0.16666665 0.16666665 0.00000000 41
0.14583332 0.14583332 0.00000000 42
0.12499999 0.12499999 0.00000000 43
0.10416666 0.10416666 0.00000000 44
0.08333333 0.08333333 0.00000000 45
0.06249999 0.06249999 0.00000000 46
0.04166666 0.04166666 0.00000000 47
0.02083333 0.02083333 0.00000000 48
0.00000000 0.00000000 0.00000000 49
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