Please make sure that the Kpoint of the primitive grephene unit cell is included in your kmesh.<br><br><div class="gmail_quote">On Mon, May 21, 2012 at 8:13 PM, Cao TF <span dir="ltr"><<a href="mailto:tfcao@theory.issp.ac.cn" target="_blank">tfcao@theory.issp.ac.cn</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><u></u>
<div>
<div>Dear QE users,
<br>
I have calculated the density of states (DOS) of pure graphene. The supercell used in my work is a rectangular cell containing 60 carbon atoms. But something has puzzled me greatly. There is always a little energy gap (~0.2 eV) in the DOS, which contracts with the fact that graphene is zero gap semiconductor. Although I have change many parameters. This problem has not been solved. Here I give the input file and I will be greatly appreciated if you can give me some suggestions.
<br>
For <a href="http://scf.in" target="_blank">scf.in</a>
<br>
&CONTROL
<br>
title = 'graphene layer' ,
<br>
calculation = 'scf' ,
<br>
restart_mode = 'from_scratch' ,
<br>
outdir = './tmp' ,
<br>
pseudo_dir = '~pseudo' ,
<br>
prefix = 'graphene' ,
<br>
/
<br>
&SYSTEM
<br>
ibrav = 8 ,
<br>
a = 12.31 , b = 12.79312342 , c = 12.000 ,
<br>
nat = 60 ,
<br>
ntyp = 1 ,
<br>
occupations = 'smearing' ,
<br>
tot_charge = 0.0,
<br>
degauss = 0.02 ,
<br>
smearing = 'mp' ,
<br>
nspin = 2 ,
<br>
starting_magnetization(1) = 0.5 ,
<br>
ecutwfc = 30.0 ,
<br>
ecutrho = 300.0 ,
<br>
/
<br>
&ELECTRONS
<br>
conv_thr = 1.0d-8 ,
<br>
mixing_mode = 'local-TF' ,
<br>
mixing_beta = 0.7 ,
<br>
diagonalization = 'david' ,
<br>
/
<br>
ATOMIC_SPECIES
<br>
C 12.0107 C.pbe-rrkjus.UPF
<br>
ATOMIC_POSITIONS crystal
<br>
C 0.0000000 0.0000000 0.50000000
<br>
C 0.10000000 5.55555671E-02 0.50000000
<br>
C 0.10000000 0.16666667 0.50000000
<br>
C 0.0000000 0.22222224 0.50000000
<br>
C 0.0000000 0.33333334 0.50000000
<br>
C 0.10000000 0.38888890 0.50000000
<br>
C 0.10000000 0.50000000 0.50000000
<br>
C 0.0000000 0.55555558 0.50000000
<br>
C 0.0000000 0.66666669 0.50000000
<br>
C 0.10000000 0.72222227 0.50000000
<br>
C 0.10000000 0.83333337 0.50000000
<br>
C 0.0000000 0.88888896 0.50000000
<br>
C 0.20000000 0.0000000 0.50000000
<br>
C 0.30000001 5.55555671E-02 0.50000000
<br>
C 0.30000001 0.16666667 0.50000000
<br>
C 0.20000000 0.22222224 0.50000000
<br>
C 0.20000000 0.33333334 0.50000000
<br>
C 0.30000001 0.38888890 0.50000000
<br>
C 0.30000001 0.50000000 0.50000000
<br>
C 0.20000000 0.55555558 0.50000000
<br>
C 0.20000000 0.66666669 0.50000000
<br>
C 0.30000001 0.72222227 0.50000000
<br>
C 0.30000001 0.83333337 0.50000000
<br>
C 0.20000000 0.88888896 0.50000000
<br>
C 0.40000001 0.0000000 0.50000000
<br>
C 0.50000000 5.55555671E-02 0.50000000
<br>
C 0.50000000 0.16666667 0.50000000
<br>
C 0.40000001 0.22222224 0.50000000
<br>
C 0.40000001 0.33333334 0.50000000
<br>
C 0.50000000 0.38888890 0.50000000
<br>
C 0.50000000 0.50000000 0.50000000
<br>
C 0.40000001 0.55555558 0.50000000
<br>
C 0.40000001 0.66666669 0.50000000
<br>
C 0.50000000 0.72222227 0.50000000
<br>
C 0.50000000 0.83333337 0.50000000
<br>
C 0.40000001 0.88888896 0.50000000
<br>
C 0.60000002 0.0000000 0.50000000
<br>
C 0.70000005 5.55555671E-02 0.50000000
<br>
C 0.70000005 0.16666667 0.50000000
<br>
C 0.60000002 0.22222224 0.50000000
<br>
C 0.60000002 0.33333334 0.50000000
<br>
C 0.70000005 0.38888890 0.50000000
<br>
C 0.70000005 0.50000000 0.50000000
<br>
C 0.60000002 0.55555558 0.50000000
<br>
C 0.60000002 0.66666669 0.50000000
<br>
C 0.70000005 0.72222227 0.50000000
<br>
C 0.70000005 0.83333337 0.50000000
<br>
C 0.60000002 0.88888896 0.50000000
<br>
C 0.80000001 0.0000000 0.50000000
<br>
C 0.90000004 5.55555671E-02 0.50000000
<br>
C 0.90000004 0.16666667 0.50000000
<br>
C 0.80000001 0.22222224 0.50000000
<br>
C 0.80000001 0.33333334 0.50000000
<br>
C 0.90000004 0.38888890 0.50000000
<br>
C 0.90000004 0.50000000 0.50000000
<br>
C 0.80000001 0.55555558 0.50000000
<br>
C 0.80000001 0.66666669 0.50000000
<br>
C 0.90000004 0.72222227 0.50000000
<br>
C 0.90000004 0.83333337 0.50000000
<br>
C 0.80000001 0.88888896 0.50000000
<br>
K_POINTS automatic
<br>
8 8 1 0 0 0
<br>
For <a href="http://nscf.in" target="_blank">nscf.in</a>
<br>
&CONTROL
<br>
title = 'graphene layer' ,
<br>
calculation = 'nscf' ,
<br>
restart_mode = 'from_scratch' ,
<br>
outdir = './tmp' ,
<br>
pseudo_dir = '/lustre/ISSP2/tfcao/pseudo' ,
<br>
prefix = 'graphene' ,
<br>
/
<br>
&SYSTEM
<br>
ibrav = 8 ,
<br>
a = 12.31 , b = 12.79312342 , c = 12.000 ,
<br>
nat = 60 ,
<br>
ntyp = 1 ,
<br>
occupations = 'tetrahedra' ,
<br>
tot_charge = 0.0,
<br>
nspin = 2 ,
<br>
starting_magnetization(1) = 0.5 ,
<br>
ecutwfc = 30.0 ,
<br>
ecutrho = 300.0 ,
<br>
/
<br>
&ELECTRONS
<br>
conv_thr = 1.0d-8 ,
<br>
mixing_mode = 'local-TF' ,
<br>
mixing_beta = 0.7 ,
<br>
diagonalization = 'david' ,
<br>
/
<br>
ATOMIC_SPECIES
<br>
C 12.0107 C.pbe-rrkjus.UPF
<br>
For <a href="http://dos.in" target="_blank">dos.in</a>
<br>
&inputpp
<br>
prefix = 'graphene' ,
<br>
outdir = './tmp' ,
<br>
Emin = -4.0 ,
<br>
Emax = 4.0 ,
<br>
DeltaE = 0.01 ,
<br>
fildos = graphene.dos ,
<br>
/
<br>
The accessory is the DOS I have got.
<br>
I am sorry for such a long file. I hope that you can give some suggestions.
<br>
======================================================================
<br>
Tengfei Cao, Research Laboratory for Computational Materials Sciences,
<br>
Instutue of Solid State Physics,the Chinese Academy of Sciences,
<br>
<br>
======================================================================
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<br>
93,2 ΅ΧΆΛ
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1,2 Ά₯ΆΛ
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br>____________________________________<br>Hui Wang<br>School of physics, Fudan University, Shanghai, China<br>