<div dir="ltr"><div class="gmail_default" style="font-family:tahoma,sans-serif">Dear QE users<br><br><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif">i have run band structure calculation for Si unit cell and 2x2x2 super-cell. as far as i know the both band structure should be same since 2x2x2 super-cell is = simply repeating unit cell in space twice all direction.<br>
<br></div><div class="gmail_default" style="font-family:tahoma,sans-serif">but here i have different band structures and do not know why this occurs. below i attached input of Si unit & 2x2x2 supercell.<br></div><div class="gmail_default" style="font-family:tahoma,sans-serif">
<br><b><u>input for Si 2x2x2 supercell</u></b><br># self-consistent calculation<br>cat > <a href="http://si.scf.in">si.scf.in</a> << EOF<br> &control<br> calculation='scf'<br> restart_mode='from_scratch',<br>
prefix='si'<br> pseudo_dir = '/home/physics/Desktop/espresso-5.0.1/pseudo/',<br> outdir='/home/physics/tmp/'<br> /<br> &system<br> ibrav = 2,<br> A = 10.7952 ,<br>
B = 10.7952 ,<br> C = 10.7952 ,<br> cosAB = 0 ,<br> cosAC = 0 ,<br> cosBC = 0 ,<br> nat = 16,<br>
ntyp = 1,<br> ecutwfc = 18.0 ,<br> ecutrho = 72 ,<br> occupations = 'smearing' ,<br> degauss = 0.01 ,<br> smearing = 'gaussian' ,<br>
<br>/<br> &ELECTRONS<br> conv_thr = 1.0d-6,<br> mixing_beta = 0.3,<br> /<br>ATOMIC_SPECIES<br> Si 28.08600 Si.pz-mt_fhi.UPF <br>ATOMIC_POSITIONS angstrom <br> Si 0.000000000 0.000000000 0.000000000 <br>
Si 1.349401350 1.349401350 1.349401350 <br> Si -2.698802700 2.698802700 0.000000000 <br> Si -1.349401350 4.048204050 1.349401350 <br> Si 0.000000000 2.698802700 2.698802700 <br>
Si 1.349401350 4.048204050 4.048204050 <br> Si -2.698802700 5.397605400 2.698802700 <br> Si -1.349401350 6.747006750 4.048204050 <br> Si -2.698802700 0.000000000 2.698802700 <br>
Si -1.349401350 1.349401350 4.048204050 <br> Si -5.397605400 2.698802700 2.698802700 <br> Si -4.048204050 4.048204050 4.048204050 <br> Si -2.698802700 2.698802700 5.397605400 <br>
Si -1.349401350 4.048204050 6.747006750 <br> Si -5.397605400 5.397605400 5.397605400 <br> Si -4.048204050 6.747006750 6.747006750 <br>K_POINTS automatic<br>2 2 2 0 0 0<br>EOF <br>
</div><div class="gmail_default" style="font-family:tahoma,sans-serif"><br># band structure calculation along high-symmetry lines<br>cat > <a href="http://si.band.in">si.band.in</a> << EOF<br></div><div class="gmail_default" style="font-family:tahoma,sans-serif">
&control<br> calculation='bands'<br> pseudo_dir = '/home/physics/Desktop/espresso-5.0.1/pseudo/',<br> outdir='/home/physics/tmp/',<br> prefix='si'<br> /<br> &system<br>
ibrav = 2,<br> A = 10.7952 ,<br> B = 10.7952 ,<br> C = 10.7952 ,<br> cosAB = 0 ,<br> cosAC = 0 ,<br>
cosBC = 0 ,<br> nat = 16,<br> ntyp = 1,<br> ecutwfc = 18.0 ,<br> ecutrho = 72 ,<br> occupations = 'smearing' ,<br>
degauss = 0.01 ,<br> smearing = 'gaussian' ,<br> nbnd = 50,<br> /<br> &ELECTRONS<br> conv_thr = 1.0d-6 ,<br> mixing_beta = 0.3 ,<br>
/<br>ATOMIC_SPECIES<br> Si 28.08600 Si.pz-mt_fhi.UPF <br>ATOMIC_POSITIONS angstrom <br> Si 0.000000000 0.000000000 0.000000000 <br> Si 1.349401350 1.349401350 1.349401350 <br> Si -2.698802700 2.698802700 0.000000000 <br>
Si -1.349401350 4.048204050 1.349401350 <br> Si 0.000000000 2.698802700 2.698802700 <br> Si 1.349401350 4.048204050 4.048204050 <br> Si -2.698802700 5.397605400 2.698802700 <br>
Si -1.349401350 6.747006750 4.048204050 <br> Si -2.698802700 0.000000000 2.698802700 <br> Si -1.349401350 1.349401350 4.048204050 <br> Si -5.397605400 2.698802700 2.698802700 <br>
Si -4.048204050 4.048204050 4.048204050 <br> Si -2.698802700 2.698802700 5.397605400 <br> Si -1.349401350 4.048204050 6.747006750 <br> Si -5.397605400 5.397605400 5.397605400 <br>
Si -4.048204050 6.747006750 6.747006750 <br>K_POINTS<br> 36<br> 0.5 0.5 0.5 1<br> 0.4 0.4 0.4 2<br> 0.3 0.3 0.3 3<br> 0.2 0.2 0.2 4<br> 0.1 0.1 0.1 5<br> 0.0 0.0 0.0 6<br> 0.0 0.0 0.1 7<br>
0.0 0.0 0.2 8<br> 0.0 0.0 0.3 9<br> 0.0 0.0 0.4 10<br> 0.0 0.0 0.5 11<br> 0.0 0.0 0.6 12<br> 0.0 0.0 0.7 13<br> 0.0 0.0 0.8 14<br> 0.0 0.0 0.9 15<br> 0.0 0.0 1.0 16<br> 0.0 0.1 1.0 17<br> 0.0 0.2 1.0 18<br>
0.0 0.3 1.0 19<br> 0.0 0.4 1.0 20<br> 0.0 0.5 1.0 21<br> 0.0 0.6 1.0 22<br> 0.0 0.7 1.0 23<br> 0.0 0.8 1.0 24<br> 0.0 0.9 1.0 25<br> 0.0 1.0 1.0 26<br> 0.0 0.9 0.9 27<br> 0.0 0.8 0.8 28<br> 0.0 0.7 0.7 29<br>
0.0 0.6 0.6 30<br> 0.0 0.5 0.5 31<br> 0.0 0.4 0.4 32<br> 0.0 0.3 0.3 33<br> 0.0 0.2 0.2 34<br> 0.0 0.1 0.1 35<br> 0.0 0.0 0.0 36<br></div><div class="gmail_default" style="font-family:tahoma,sans-serif">EOF<br>
<br><u></u></div><div class="gmail_default" style="font-family:tahoma,sans-serif"><b><u>Si Unitcell:</u></b><br># self-consistent calculation<br>cat > <a href="http://si.scf.in">si.scf.in</a> << EOF<br> &control<br>
calculation='scf'<br> restart_mode='from_scratch',<br> prefix='si'<br> pseudo_dir = '$PSEUDO_DIR/',<br> outdir='$TMP_DIR/'<br> /<br> &system<br> ibrav= 2, <br>
A = 5.397, <br> B =5.397, <br> C = 5.397,<br> cosAB = 0 ,<br> cosAC = 0 ,<br> cosBC = 0 , nat= 2, ntyp= 1,<br> ecutwfc =18.0, occupations = 'smearing', degauss = 0.01 smearing = 'gaussian' ,<br>
/<br> &electrons<br> conv_thr = 1.0d-6<br> mixing_beta = 0.3<br> /<br>ATOMIC_SPECIES<br> Si 28.086 Si.pz-vbc.UPF<br>ATOMIC_POSITIONS angstrom<br>Si 0.0000000000 0.0000000000 0.0000000000<br>Si 1.3494013500 1.3494013500 1.3494013500<br>
K_POINTS automatic<br>6 6 6 0 0 0<br>EOF<br><br># band structure calculation along high-symmetry lines<br>cat > <a href="http://si.band.in">si.band.in</a> << EOF<br> &control<br> calculation='bands'<br>
pseudo_dir = '$PSEUDO_DIR/',<br> outdir='$TMP_DIR/',<br> prefix='si'<br> /<br> &system<br> ibrav= 2,<br> A = 5.397, <br> B =5.397, <br> C = 5.397,<br> cosAB = 0 ,<br> cosAC = 0 ,<br>
cosBC = 0 ,<br> nat= 2, ntyp= 1,<br> ecutwfc =18.0, nbnd = 28,<br> /<br> &electrons<br> /<br>ATOMIC_SPECIES<br> Si 28.086 Si.pz-vbc.UPF<br>ATOMIC_POSITIONS angstrom<br>Si 0.0000000000 0.0000000000 0.0000000000<br>
Si 1.3494013500 1.3494013500 1.3494013500<br>K_POINTS<br> 36<br> 0.5 0.5 0.5 1<br> 0.4 0.4 0.4 2<br> 0.3 0.3 0.3 3<br> 0.2 0.2 0.2 4<br> 0.1 0.1 0.1 5<br> 0.0 0.0 0.0 6<br> 0.0 0.0 0.1 7<br> 0.0 0.0 0.2 8<br>
0.0 0.0 0.3 9<br> 0.0 0.0 0.4 10<br> 0.0 0.0 0.5 11<br> 0.0 0.0 0.6 12<br> 0.0 0.0 0.7 13<br> 0.0 0.0 0.8 14<br> 0.0 0.0 0.9 15<br> 0.0 0.0 1.0 16<br> 0.0 0.1 1.0 17<br> 0.0 0.2 1.0 18<br> 0.0 0.3 1.0 19<br>
0.0 0.4 1.0 20<br> 0.0 0.5 1.0 21<br> 0.0 0.6 1.0 22<br> 0.0 0.7 1.0 23<br> 0.0 0.8 1.0 24<br> 0.0 0.9 1.0 25<br> 0.0 1.0 1.0 26<br> 0.0 0.9 0.9 27<br> 0.0 0.8 0.8 28<br> 0.0 0.7 0.7 29<br> 0.0 0.6 0.6 30<br>
0.0 0.5 0.5 31<br> 0.0 0.4 0.4 32<br> 0.0 0.3 0.3 33<br> 0.0 0.2 0.2 34<br> 0.0 0.1 0.1 35<br> 0.0 0.0 0.0 36<br></div><div class="gmail_default" style="font-family:tahoma,sans-serif">EOF<br><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif">
<b>thank you <br></b></div><div class="gmail_default" style="font-family:tahoma,sans-serif"><br></div><div><div dir="ltr"><span style="background-color:rgb(243,243,243)"><span style="color:rgb(0,0,255)"><span style="font-family:georgia,serif"><i><span style="font-size:12pt;line-height:115%"><b>_________________________<br>
</b></span></i></span></span><span style="font-family:georgia,serif"><i><span style="color:rgb(0,0,255)"><font><span style="line-height:115%"><b><span style="line-height:115%"><br>Muthu.V</span><span style="line-height:150%"><br>
Madurai Kamaraj
Universit</span></b></span><span style="line-height:115%"><b><span style="line-height:150%">y</span><span style="line-height:115%"></span></b></span></font></span><span style="font-size:12pt;line-height:115%;color:black"><b><span style="color:rgb(0,0,255)"><span style="font-family:georgia,serif"><i><span style="font-size:12pt;line-height:115%"><b><span></span><br>
</b></span></i></span>__________________________</span><br></b></span></i></span></span><br><span style="font-family:georgia,serif"><i><span style="font-size:12pt;line-height:115%;color:black"><b></b></span></i></span></div>
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