[Pw_forum] negative values in the electron-phonon calculation.
matteo giantomassi
gmatteo at gmail.com
Thu Sep 9 12:47:35 CEST 2004
Dear Pwscf users,
I want to calculate the electron-phonon interaction in CaAlSi using
LDA pseudopotentials.
The structure has been optimized and all phonon frequences are positive
but some values of lambda(q) e gamma(q) are negative!.
***********************************************************************************************
This is the test script i'm using:
***********************************************************************************************
#/bin/sh
. ../environment_variables
# self-consistent calculation
cat > caalsi.scf.in << EOF
&control
calculation='scf'
restart_mode='from_scratch',
tstress = .true.
tprnfor = .true.
prefix='caalsi',
pseudo_dir = '$PSEUDO_DIR/',
outdir='$TMP_DIR/'
/
&system
ibrav= 4, celldm(1) =7.93912, celldm(3)=1.18356, nat= 3, ntyp= 3,
ecutwfc =20, nbnd=12,
occupations='smearing', degauss=0.006, smearing='gaussian',
/
&electrons
conv_thr = 1.0d-8
mixing_beta = 0.7
/
ATOMIC_SPECIES
Ca 40.078 Ca.pz-n-vbc.UPF
Al 26.98154 Al.pz-vbc.UPF
Si 28.08550 Si.pz-vbc.UPF
ATOMIC_POSITIONS crystal
Ca 0 0 0
Al 0.333333333 0.666666666 0.5
Si 0.666666666 0.333333333 0.5
K_POINTS automatic
12 12 12 0 0 0
EOF
$PW_ROOT/bin/pw.x < caalsi.scf.in > caalsi.scf.out
#
# These are k-points of a (666) uniform grid in the irreducible# Brillouin Zone
qpoints="0.1666667,0.0962250,0.0000000
0.3333333,0.1924501,0.0000000
0.5000000,0.2886751,0.0000000
0.1666667,0.2886751,0.0000000
0.3333333,0.3849002,0.0000000
0.3333333,0.5773503,0.0000000
0.0000000,0.0000000,0.1408181
0.1666667,0.0962250,0.1408181
0.3333333,0.1924501,0.1408181
0.5000000,0.2886751,0.1408181
0.1666667,0.2886751,0.1408181
0.3333333,0.3849002,0.1408181
0.3333333,0.5773503,0.1408181
0.0000000,0.0000000,0.2816362
0.1666667,0.0962250,0.2816362
0.3333333,0.1924501,0.2816362
0.5000000,0.2886751,0.2816362
0.1666667,0.2886751,0.2816362
0.3333333,0.3849002,0.2816362
0.3333333,0.5773503,0.2816362
0.0000000,0.0000000,0.4224543
0.1666667,0.0962250,0.4224543
0.3333333,0.1924501,0.4224543
0.5000000,0.2886751,0.4224543
0.1666667,0.2886751,0.4224543
0.3333333,0.3849002,0.4224543
0.3333333,0.5773503,0.4224543"
for qpoint in $qpoints ; do
#
# non self-consistent calculation
#
qx=`echo $qpoint | cut -d, -f1`
qy=`echo $qpoint | cut -d, -f2`
qz=`echo $qpoint | cut -d, -f3`
cat > caalsi.nscf.in << EOF
&control
calculation='phonon'
restart_mode='from_scratch',
prefix='caalsi',
pseudo_dir = '$PSEUDO_DIR/',
outdir='$TMP_DIR/'
/
&system
ibrav= 4, celldm(1) =7.93912, celldm(3)= 1.18356, nat= 3, ntyp= 3,
ecutwfc =20, nbnd=12, occupations='smearing',
degauss=0.006, smearing='gaussian',
/
&electrons
conv_thr = 1.0d-8
/
&phonon
xqq(1) = $qx, xqq(2) = $qy, xqq(3) = $qz
/
ATOMIC_SPECIES
Ca 40.078 Ca.pz-n-vbc.UPF
Al 26.98154 Al.pz-vbc.UPF
Si 28.08550 Si.pz-vbc.UPF
ATOMIC_POSITIONS crystal
Ca 0 0 0
Al 0.333333333 0.666666666 0.5
Si 0.666666666 0.333333333 0.5
K_POINTS automatic
6 6 6 0 0 0
EOF
$PW_ROOT/bin/pw.x < caalsi.nscf.in >> caalsi.nscf.out
cat > caalsi.ph.in << EOF
phonons of caalsi at $qpoint
&inputph
tr2_ph=1.0d-10,
prefix='caalsi',
amass(1)=40.078,
amass(2)=26.98154,
amass(3)=28.08550,
outdir='$TMP_DIR/',
fildyn='dyn.$qpoint'
fildvscf='caalsidv'
/
$qpoint
EOF
$PW_ROOT/bin/ph.x < caalsi.ph.in >> caalsi.ph.out
cat > caalsi.nscf2.in << EOF
&control
calculation='phonon'
restart_mode='from_scratch',
prefix='caalsi',
pseudo_dir = '$PSEUDO_DIR/',
outdir='$TMP_DIR/'
/
&system
ibrav= 4, celldm(1) =7.93912, celldm(3)= 1.18356, nat= 3, ntyp= 3,
ecutwfc =20, nbnd=12, occupations='smearing',
degauss=0.006, smearing='gaussian',
/
&electrons
conv_thr = 1.0d-8
/
&phonon
xqq(1) = $qx, xqq(2) = $qy, xqq(3) = $qz
/
ATOMIC_SPECIES
Ca 40.078 Ca.pz-n-vbc.UPF
Al 26.98154 Al.pz-vbc.UPF
Si 28.08550 Si.pz-vbc.UPF
ATOMIC_POSITIONS crystal
Ca 0 0 0
Al 0.333333333 0.666666666 0.5
Si 0.666666666 0.333333333 0.5
K_POINTS automatic
12 12 12 0 0 0
EOF
$PW_ROOT/bin/pw.x < caalsi.nscf2.in >> caalsi.nscf2.out
cat >caalsi.elph.in<<EOF
caalsi el-phonon at $qpoint
&inputph
prefix='caalsi',
tr2_ph=1.0d-10,
amass(1)=40.078,
amass(2)=26.98154,
amass(3)=28.08550,
outdir='$TMP_DIR/',
filelph='elph.$qpoint'
fildyn='dyn.$qpoint'
fildvscf='caalsidv'
elph=.true.,
trans=.false.,
/
$qpoint
EOF
$PW_ROOT/bin/ph.x < caalsi.elph.in >> caalsi.elph.$qpoint.out
done
***********************************************************************************************
This is one of the output file with negative frequences:
***********************************************************************************************
0.00000000 0.00000000 0.14081810 10 9
0.236982E-06 0.236982E-06 0.329897E-06 0.704514E-06 0.185522E-05
0.185522E-05
0.382096E-05 0.150028E-04 0.150028E-04
Gaussian Broadening: 0.010 Ry, ngauss= 1
DOS = 6.132378 states/spin/Ry/Unit Cell at Ef= 5.209036 eV
lambda( 1)= 0.000657 gamma= 0.009865 GHz
lambda( 2)= 0.000657 gamma= 0.009865 GHz
lambda( 3)= 0.043325 gamma= 0.905868 GHz
lambda( 4)= 0.237444 gamma= 10.602345 GHz
lambda( 5)= 0.001142 gamma= 0.134227 GHz
lambda( 6)= 0.001142 gamma= 0.134227 GHz
lambda( 7)= 0.013474 gamma= 3.263082 GHz
lambda( 8)= 0.000120 gamma= 0.113898 GHz
lambda( 9)= 0.000120 gamma= 0.113898 GHz
Gaussian Broadening: 0.020 Ry, ngauss= 1
DOS = 6.977768 states/spin/Ry/Unit Cell at Ef= 5.211531 eV
lambda( 1)= 0.001969 gamma= 0.033645 GHz
lambda( 2)= 0.001969 gamma= 0.033645 GHz
lambda( 3)= 0.151148 gamma= 3.596009 GHz
lambda( 4)= 0.175232 gamma= 8.903105 GHz
lambda( 5)= 0.002364 gamma= 0.316288 GHz
lambda( 6)= 0.002364 gamma= 0.316288 GHz
lambda( 7)= 0.028882 gamma= 7.958773 GHz
lambda( 8)= 0.039194 gamma= 42.406162 GHz
lambda( 9)= 0.039194 gamma= 42.406162 GHz
Gaussian Broadening: 0.030 Ry, ngauss= 1
DOS = 7.529356 states/spin/Ry/Unit Cell at Ef= 5.209391 eV
lambda( 1)= 0.003371 gamma= 0.062170 GHz
lambda( 2)= 0.003371 gamma= 0.062170 GHz
lambda( 3)= 0.166041 gamma= 4.262610 GHz
lambda( 4)= 0.168241 gamma= 9.223663 GHz
lambda( 5)= 0.002268 gamma= 0.327434 GHz
lambda( 6)= 0.002268 gamma= 0.327434 GHz
lambda( 7)= 0.028544 gamma= 8.487177 GHz
lambda( 8)= 0.039431 gamma= 46.034902 GHz
lambda( 9)= 0.039431 gamma= 46.034902 GHz
Gaussian Broadening: 0.040 Ry, ngauss= 1
DOS = 7.670877 states/spin/Ry/Unit Cell at Ef= 5.203249 eV
lambda( 1)= 0.001583 gamma= 0.029750 GHz
lambda( 2)= 0.001583 gamma= 0.029750 GHz
lambda( 3)= 0.149597 gamma= 3.912651 GHz
lambda( 4)= 0.148433 gamma= 8.290641 GHz
lambda( 5)= 0.001961 gamma= 0.288411 GHz
lambda( 6)= 0.001961 gamma= 0.288411 GHz
lambda( 7)= 0.025160 gamma= 7.621627 GHz
lambda( 8)= 0.036271 gamma= 43.141752 GHz
lambda( 9)= 0.036271 gamma= 43.141752 GHz
Gaussian Broadening: 0.050 Ry, ngauss= 1
DOS = 7.619871 states/spin/Ry/Unit Cell at Ef= 5.192300 eV
lambda( 1)= -0.002955 gamma= -0.055152 GHz
lambda( 2)= -0.002955 gamma= -0.055152 GHz
lambda( 3)= 0.137191 gamma= 3.564312 GHz
lambda( 4)= 0.157767 gamma= 8.753367 GHz
lambda( 5)= 0.001361 gamma= 0.198827 GHz
lambda( 6)= 0.001361 gamma= 0.198827 GHz
lambda( 7)= 0.022826 gamma= 6.868779 GHz
lambda( 8)= 0.034416 gamma= 40.662960 GHz
lambda( 9)= 0.034416 gamma= 40.662960 GHz
Gaussian Broadening: 0.060 Ry, ngauss= 1
DOS = 7.461279 states/spin/Ry/Unit Cell at Ef= 5.177789 eV
lambda( 1)= -0.007504 gamma= -0.137142 GHz
lambda( 2)= -0.007504 gamma= -0.137142 GHz
lambda( 3)= 0.127975 gamma= 3.255675 GHz
lambda( 4)= 0.173138 gamma= 9.406301 GHz
lambda( 5)= 0.000739 gamma= 0.105748 GHz
lambda( 6)= 0.000739 gamma= 0.105748 GHz
lambda( 7)= 0.021131 gamma= 6.226166 GHz
lambda( 8)= 0.033006 gamma= 38.186120 GHz
lambda( 9)= 0.033006 gamma= 38.186120 GHz
Gaussian Broadening: 0.070 Ry, ngauss= 1
DOS = 7.283095 states/spin/Ry/Unit Cell at Ef= 5.160627 eV
lambda( 1)= -0.018199 gamma= -0.324639 GHz
lambda( 2)= -0.018199 gamma= -0.324639 GHz
lambda( 3)= 0.117780 gamma= 2.924747 GHz
lambda( 4)= 0.186663 gamma= 9.898900 GHz
lambda( 5)= -0.000793 gamma= -0.110793 GHz
lambda( 6)= -0.000793 gamma= -0.110793 GHz
lambda( 7)= 0.019455 gamma= 5.595627 GHz
lambda( 8)= 0.031702 gamma= 35.801292 GHz
lambda( 9)= 0.031702 gamma= 35.801292 GHz
Gaussian Broadening: 0.080 Ry, ngauss= 1
DOS = 7.134589 states/spin/Ry/Unit Cell at Ef= 5.141263 eV
lambda( 1)= -0.038412 gamma= -0.671230 GHz
lambda( 2)= -0.038412 gamma= -0.671230 GHz
lambda( 3)= 0.103604 gamma= 2.520264 GHz
lambda( 4)= 0.196871 gamma= 10.227331 GHz
lambda( 5)= -0.003826 gamma= -0.523386 GHz
lambda( 6)= -0.003826 gamma= -0.523386 GHz
lambda( 7)= 0.017477 gamma= 4.924072 GHz
lambda( 8)= 0.030406 gamma= 33.637463 GHz
lambda( 9)= 0.030406 gamma= 33.637463 GHz
Gaussian Broadening: 0.090 Ry, ngauss= 1
DOS = 7.033187 states/spin/Ry/Unit Cell at Ef= 5.120081 eV
lambda( 1)= -0.059546 gamma= -1.025752 GHz
lambda( 2)= -0.059546 gamma= -1.025752 GHz
lambda( 3)= 0.086926 gamma= 2.084514 GHz
lambda( 4)= 0.203333 gamma= 10.412934 GHz
lambda( 5)= -0.007202 gamma= -0.971260 GHz
lambda( 6)= -0.007202 gamma= -0.971260 GHz
lambda( 7)= 0.015317 gamma= 4.254199 GHz
lambda( 8)= 0.029198 gamma= 31.841996 GHz
lambda( 9)= 0.029198 gamma= 31.841996 GHz
Gaussian Broadening: 0.100 Ry, ngauss= 1
DOS = 6.985853 states/spin/Ry/Unit Cell at Ef= 5.097830 eV
lambda( 1)= -0.067654 gamma= -1.157586 GHz
lambda( 2)= -0.067654 gamma= -1.157586 GHz
lambda( 3)= 0.071972 gamma= 1.714293 GHz
lambda( 4)= 0.206694 gamma= 10.513791 GHz
lambda( 5)= -0.008860 gamma= -1.186849 GHz
lambda( 6)= -0.008860 gamma= -1.186849 GHz
lambda( 7)= 0.013326 gamma= 3.676327 GHz
lambda( 8)= 0.028227 gamma= 30.575707 GHz
lambda( 9)= 0.028227 gamma= 30.575707 GHz
***********************************************************************************************
Where is the problem?. Any help would be appreciated!
Thanks
Matteo Giantomassi.
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