<p style="margin: 0px; padding: 0px;">Dear all,</p><p style="margin: 0px; padding: 0px;"> regardless the pseudopotentials I use for my optimization and the kpoint sampling, I always obtain that ZB phase of ZnO is (slightly) more stable than WZ.</p><p style="margin: 0px; padding: 0px;"><br></p><p style="margin: 0px; padding: 0px;">Since I would like to make HSE calculations on such systems I would like to have an already well-ordered (in terms of energy, of course) structures at PBE level. (In my case WZ and ZB look almost degenerate, but always with ZB slightly more stable than WZ)<br></p><p style="margin: 0px; padding: 0px;"><br></p><p style="margin: 0px; padding: 0px;">Can anyone help me to refine parameters that allow me to obtain E WZ < E ZB. Here you find the two inputs.</p><p style="margin: 0px; padding: 0px;"><br></p><p style="margin: 0px; padding: 0px;">Wurtzite ZnO</p><p style="margin: 0px; padding: 0px;">&CONTROL<br> calculation = "scf"<br> pseudo_dir = './'<br> outdir='./',<br> restart_mode="from_scratch",<br> prefix='ZnO_WZ',<br> tprnfor = .true.,<br> tstress = .true.,<br> wf_collect=.true.,<br>/<br>&SYSTEM<br> ibrav= 4, celldm(1) =6.13821, celldm(3)=1.6023951, nat= 4, ntyp= 2,<br> ecutwfc =90.0, nbnd = 80, nspin=2, tot_magnetization=0,<br>/<br>&ELECTRONS<br> diagonalization='david'<br> mixing_mode = 'plain'<br> mixing_beta = 0.7<br> conv_thr = 1.0d-8<br>/<br>ATOMIC_SPECIES<br> Zn 65.38 Zn-GGA-pbe.fhi.UPF<br> O 15.9994 O-GGA-pbe.fhi.UPF<br>ATOMIC_POSITIONS (crystal)<br> Zn 0.33333 0.66667 0.00000<br> Zn 0.66667 0.33333 0.50000<br> O 0.33333 0.66667 0.38210<br> O 0.66667 0.33333 0.88210<br>K_POINTS (automatic)<br>12 12 9 0 0 0<br></p><p style="margin: 0px; padding: 0px;"><br></p><p style="margin: 0px; padding: 0px;">total energy = -285.55060915 Ry/2 = -142.7753045750<br></p><p style="margin: 0px; padding: 0px;"><br></p><p style="margin: 0px; padding: 0px;"><br></p><p style="margin: 0px; padding: 0px;"><br></p><p style="margin: 0px; padding: 0px;">Zincblende ZnO</p><p style="margin: 0px; padding: 0px;">&control<br> calculation = 'scf'<br> restart_mode='from_scratch',<br> prefix='ZnO_ZB',<br> tprnfor = .true.,<br> tstress = .true.,<br> wf_collect=.true.,<br> pseudo_dir='./',<br> outdir='./',<br>/<br>&system<br> ibrav= 1, celldm(1) =8.730534067<br> nat= 8, ntyp= 2,<br> ecutwfc =90., nbnd = 100, nspin=2, tot_magnetization=0<br>/<br>&electrons<br> diagonalization='david'<br> mixing_mode = 'plain'<br> mixing_beta = 0.7<br> conv_thr = 1.0d-8<br>/<br>ATOMIC_SPECIES<br> Zn 65.38 Zn-GGA-pbe.fhi.UPF<br> O 15.9994 O-GGA-pbe.fhi.UPF<br>ATOMIC_POSITIONS (crystal)<br>Zn 0.00000 0.00000 0.00000<br>Zn 0.00000 0.50000 0.50000<br>Zn 0.50000 0.00000 0.50000<br>Zn 0.50000 0.50000 0.00000<br>O 0.25000 0.25000 0.25000<br>O 0.25000 0.75000 0.75000<br>O 0.75000 0.75000 0.25000<br>O 0.75000 0.25000 0.75000<br>K_POINTS automatic<br>8 8 8 0 0 0<br></p><p style="margin: 0px; padding: 0px;"><br></p><p style="margin: 0px; padding: 0px;">total energy = -571.10793352 Ry/4 = -142.776983375<br></p><p style="margin: 0px; padding: 0px;"><br></p><p style="margin: 0px; padding: 0px;"><br></p><p style="margin: 0px; padding: 0px;">Thanks in advance for your help!</p><p style="margin: 0px; padding: 0px;"><br></p><p style="margin: 0px; padding: 0px;">Very best,</p><p style="margin: 0px; padding: 0px;">Giacomo</p><p style="margin: 0px; padding: 0px;"><br></p><p style="margin: 0px; padding: 0px;"><br></p><p style="margin: 0px; padding: 0px;"><tt>-- <br>
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Giacomo Giorgi, Ph.D.<br>
<br>
Yamashita & Ushiyama Laboratory,<br>
Department of Chemical System Engineering,<br>
Faculty of Engineering,<br>
The University of Tokyo.<br>
<br>
tel&fax: +81-3-5841-7286<br>
email: <a target="_self">giacomo@tcl.t.u-tokyo.ac.jp</a><br>
HP: <a href="http://www.tcl.t.u-tokyo.ac.jp/" target="_blank">http://www.tcl.t.u-tokyo.ac.jp/</a><br>
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