<div dir="ltr"><div><div><div><div><div><div>Dear <b>Никита Вакула<br><br></b></div><br></div>Have you tried the calculation considering spin polarization, nspin=2 and checking the convergence ?<br><br></div>you can try a smaller degauss value using marzari-vanderbilt or gaussian too.<br>
</div><div>Please check the smearing energy contribution to your total energy. <br></div><div><br><br></div>Are the interface atoms in close distances from each other ? I mean 1.2-2.0 angstrom for instance. If not and you put them at far distances from each other you may relax a van der Waals interaction in which the pure DFT is weak. <br>
<br></div>Do you really need such high amount of cutoff for energy and density ? <br><br></div>I hope it helps.<br><div><div><div><div><div><br><br><a name="smearing"></a><div><div><div><div><br><br><div><div class="gmail_extra">
<br clear="all"><div><br> Best Wishes, m<br><br> <br> <br><br><br>----------------------------------------<br>
Masoud Nahali<br>SUT<br><a href="mailto:masoud.nahali@gmail.com" target="_blank">masoud.nahali@gmail.com</a> <br><a href="http://alum.sharif.edu/~m_nahali" target="_blank">alum.sharif.edu/~m_nahali</a> <div><br><br></div>
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<br><br><div class="gmail_quote">On Mon, Apr 8, 2013 at 12:00 PM, <b>Никита Вакула</b> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><br>
Hi everybody,<br>
<br>
I am trying to optimize the structure of an interface between metal and insulator but have difficulties with scf convergence. Here are the changes in energies during scf cycle:<br>
estimated scf accuracy < 17.58555120 Ry<br>
estimated scf accuracy < 14.17435383 Ry<br>
estimated scf accuracy < 2.05765892 Ry<br>
estimated scf accuracy < 2.09375911 Ry<br>
estimated scf accuracy < 1.37675281 Ry<br>
estimated scf accuracy < 0.42594758 Ry<br>
estimated scf accuracy < 0.29104539 Ry<br>
estimated scf accuracy < 0.51143695 Ry<br>
estimated scf accuracy < 0.18765814 Ry<br>
estimated scf accuracy < 0.92590998 Ry<br>
estimated scf accuracy < 0.93126088 Ry<br>
estimated scf accuracy < 0.44023978 Ry<br>
estimated scf accuracy < 0.33756785 Ry<br>
estimated scf accuracy < 0.34216551 Ry<br>
estimated scf accuracy < 0.36573444 Ry<br>
estimated scf accuracy < 0.29089342 Ry<br>
estimated scf accuracy < 0.29287805 Ry<br>
estimated scf accuracy < 0.16940331 Ry<br>
estimated scf accuracy < 0.17503222 Ry<br>
estimated scf accuracy < 0.09708451 Ry<br>
estimated scf accuracy < 0.07751341 Ry<br>
estimated scf accuracy < 0.06774554 Ry<br>
estimated scf accuracy < 0.15834930 Ry<br>
estimated scf accuracy < 0.12269823 Ry<br>
estimated scf accuracy < 0.12679734 Ry<br>
estimated scf accuracy < 0.08558475 Ry<br>
estimated scf accuracy < 0.04411767 Ry<br>
estimated scf accuracy < 0.04754042 Ry<br>
<br>
I found similar posts on the forum ?but it didn't solve the problem. I checked my structure with xcrysen...it seems to be ok. I am using USPP.<br>
Any help and suggestions would be greatly appreciated.<br>
<br>
Thanks<br>
<br>
Here is my input:<br>
&CONTROL<br>
title = interface ,<br>
calculation = 'relax' ,<br>
restart_mode = 'from_scratch' ,<br>
wf_collect = .true. ,<br>
outdir = 'interface/' ,<br>
pseudo_dir = './' ,<br>
prefix = 'interface' ,<br>
lkpoint_dir = .true. ,<br>
disk_io = 'high' ,<br>
verbosity = 'high' ,<br>
nstep = 100 ,<br>
tstress = .false. ,<br>
tprnfor = .true. ,<br>
/<br>
&SYSTEM<br>
ibrav = 8,<br>
celldm(1) = 9.3957,<br>
celldm(2) = 1.7321,<br>
celldm(3) = 6.0000,<br>
nat = 72,<br>
ntyp = 3,<br>
ecutwfc = 50 ,<br>
ecutrho = 500 ,<br>
nbnd = 500,<br>
occupations = 'smearing' ,<br>
degauss = 0.025 ,<br>
smearing = 'methfessel-paxton' ,<br>
nspin = 1 ,<br>
/<br>
&ELECTRONS<br>
electron_maxstep = 200,<br>
conv_thr = 1.0d-6 ,<br>
mixing_mode = 'local-TF' ,<br>
mixing_beta = 0.1 ,<br>
mixing_ndim = 8 ,<br>
/<br>
&IONS<br>
ion_dynamics = 'bfgs' ,<br>
/<br>
ATOMIC_SPECIES<br>
? BR,<br>
<br>
N V<br></blockquote></div>--------------------------------------------------------------------------------------------------------------------<br></div></div></div></div></div></div></div></div></div></div></div></div>