Hi, wurtzite has 4 atoms in the unit cell.
Cheers Marcel On Tue, 15 Jan 2008, Helen wrote: > Hi, > 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? > Thank you for your help and advice, > Dr. Helen Eisenberg (Fritz Haber Center, Hebrew University) > > &control > calculation='scf' > restart_mode='from_scratch', > tstress = .true. > tprnfor = .true. > prefix='alas', > pseudo_dir = '$PSEUDO_DIR/', > outdir='$TMP_DIR/' > / > &system > ibrav= 4, celldm(1) =5.88, celldm(3)=1.600, nat= 2, ntyp= 2, > ecutwfc =80.0, nbnd = 8, > nr1=32, > nr2=32, > nr3=32, > ecutrho = 240.0 > / > &electrons > conv_thr = 1.0d-6 > mixing_beta = 0.7 > / > ATOMIC_SPECIES > Al 26.98 Al.vbc.UPF > N 14.007 N.pz-vbc.UPF > ATOMIC_POSITIONS > Al 0.00 0.00 0.00 > N 0.00 0.00 0.611 > K_POINTS (automatic) > 4 4 4 0 0 0 > EOF
