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<DIV><FONT face=Arial size=2>Hi,</FONT></DIV>
<DIV><FONT face=Arial size=2>I've successfully calculated the bandstructure for
zinc-blende AlN, and I wanted to do the same for wurtzite AlN but am running
into problems. I started off with a=5.88 a.u. c/a=1.600 and u=0.382 , I then
kept a and c constant and altered u. The results showed that u needed to be
smaller but when I reached u=0.369 my scf calculations stopped converging. I
tried using both cg and davidson diagonalization. I then tried keeping u
constant and altering c, I don't get convergence problems but I get
unrealistically small values of c. Also the bandgap data I'm getting is nonsense
(no band gap at all). Perhaps I have a mistake in my input file?</FONT></DIV>
<DIV><FONT face=Arial size=2>Thank you for your help and advice,</FONT></DIV>
<DIV><FONT face=Arial size=2>Dr. Helen Eisenberg (Fritz Haber Center, Hebrew
University)</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2> &control<BR>
calculation='scf'<BR>
restart_mode='from_scratch',<BR> tstress =
.true.<BR> tprnfor = .true.<BR>
prefix='alas',<BR> pseudo_dir =
'$PSEUDO_DIR/',<BR>
outdir='$TMP_DIR/'<BR> /<BR> &system
<BR> ibrav= 4, celldm(1) =5.88, celldm(3)=1.600,
nat= 2, ntyp= 2,<BR> ecutwfc =80.0, nbnd =
8,<BR> nr1=32,<BR>
nr2=32,<BR> nr3=32,<BR> ecutrho =
240.0<BR> /<BR> &electrons<BR> conv_thr =
1.0d-6<BR> mixing_beta =
0.7<BR> /<BR>ATOMIC_SPECIES<BR> Al 26.98
Al.vbc.UPF<BR> N 14.007
N.pz-vbc.UPF<BR>ATOMIC_POSITIONS<BR> Al 0.00 0.00 0.00 <BR> N 0.00
0.00 0.611<BR>K_POINTS (automatic)<BR>4 4 4 0 0
0<BR>EOF</FONT></DIV></BODY></HTML>