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<span style="" lang="EN-US"><font size="3"><font face="Calibri">Dear all,</font></font></span><font style="font-size: 12pt;" size="3"><br><br>I've tried calculated the bandstructure for Wurtzite AlN but am running into problems. I started off with experimental values ( <b>a=5.87</b> a.u. <b>c/a=1.60</b> and <b>u=0.379</b>), I then kept </font><font style="font-size: 12pt;" size="3"><br></font><font style="font-size: 12pt;" size="3"><b>a</b> and <b>u</b> constant and altered <b>c/a</b>. I found an unrealistically small value<b> c/a</b> ( <b>c=0.9</b>). I then tried keeping <b>c/a</b> constant and altering<b> a</b> my scf calculations stopped converging. </font><font style="font-size: 12pt;" size="3">Perhaps I have a mistake in my input file?</font><font style="font-size: 12pt;" size="3"><br></font><font style="font-size: 12pt;" size="3">Thank you for your help and advice.</font><br><span style="" lang="EN-US"><font size="3"><font face="Calibri">This is the input file for the "scf" calculation</font></font></span><br><br>&control<br> calculation='scf'<br> restart_mode='from_scratch',<br> tstress = .true.<br> tprnfor = .true.<br> prefix='810-28',<br> pseudo_dir = '/home/projet/pseudo/',<br> outdir='/home/projet/tp/'<br> /<br> &system<br> ibrav= 4, celldm(1) =8.12, celldm(3) =0.9, nat= 4, ntyp= 2,<br> ecutwfc =50.0, ecutrho = 600.0,<br> /<br> &electrons<br> diagonalization='david'<br> conv_thr = 1.0e-6<br> mixing_beta = 0.7<br> /<br>ATOMIC_SPECIES<br> al 26.9815 al_pz.upf<br> n 14.0067 n_pz.upf<br>ATOMIC_POSITIONS<br> al 0.333333333 0.666666667 0.000000000<br> al 0.666666667 0.333333333 0.500000000<br> n 0.333333333 0.666666667 0.379000000<br> n 0.666666667 0.333333333 0.879000000<br>K_POINTS (automatic)<br> 6 6 4 1 1 1<br><br><br><br><p style="line-height:normal;background:white" class="ecxMsoNormal"><span style="font-family:'Verdana','sans-serif';color:#2a2a2a;font-size:12pt">****************************************************************************************************************************************************************************</span><span style="font-family:'Tahoma','sans-serif';color:#2a2a2a;font-size:10pt"><br></span><span style="font-family:'Arial','sans-serif';color:#2a2a2a;font-size:10pt">Ramzi Alaya</span></p>
<span style="font-family:'Arial','sans-serif';color:#2a2a2a;font-size:10pt">E-mail : ramzialaya@hotmail.fr<br>Faculté des Sciences de Gabès, Cité Erriadh 6072 Gabès- Tunisie<br>Unité de Recherche sur les Hétéro-Epitaxies et Applications</span><br><br> </div></body>
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