[Pw_forum] Large shift of the Fermi energy - phonons, slab

[Paolo Giannozzi]

On Mon, 2013-10-28 at 09:22 +0100, Andrea Dal Corso wrote:

> Please note that the phonon code is not working in versions 5.0 
> up to 5.0.2. You need to patch 5.0.2 to obtain 5.0.3.

well, it's not that it doesn't work at all: it doesn't work in a 
few cases. Anyway, the problem mentioned by Nicki does not seem 
to me related to v.5.0.x problems. It seems like a numerical
instability, maybe triggered by the two dimensional character 
of the system

P.

> Andrea
> 
> 
> > 
> > Thanks Nicki
> > 
> > 
> > following some input/output for the phonons on (away) the Gamma point:
> > 
> > 
> > Input:
> > 
> > 
> > &inputph
> >   reduce_io = .false.
> >   tr2_ph=1.0d-12,
> >   prefix='Cu',
> >   alpha_mix = 0.150
> >   ldisp=.true.,
> >   nq1=4, nq2=4, nq3=1
> >   start_q=1
> >   last_q=1
> >   recover = .true.,
> >   amass(1)=63.546
> >   outdir="***",
> >   fildyn='Cu.dyn',
> >  /
> > 
> > 
> > Output Gamma:
> > 
> > 
> > Computing dynamical matrix for.
> >                     q = (   0.0000000   0.0000000   0.0000000 )
> > 
> > 
> >       7 Sym.Ops. (with q -> -q+G )
> > //
> > Atomic displacements:
> >      There are  42 irreducible representations
> > //
> >  Representation #  1 mode #   1
> > 
> > 
> >      Self-consistent Calculation
> > 
> > 
> >      Pert. #  1: Fermi energy shift (Ry) =    -0.1403E+01
> >  -0.8470E-21
> >      
> >       iter #   1 total cpu time :   168.5 secs   av.it.:   6.1
> >       thresh= 0.100E-01 alpha_mix =  0.150 |ddv_scf|^2 =  0.277E+00
> > //
> >       Pert. #  1: Fermi energy shift (Ry) =     0.1555E+08
> >  -0.8882E-15
> > //
> >       iter # 100 total cpu time :  2038.3 secs   av.it.:  25.3
> >       thresh= 0.100E-01 alpha_mix =  0.150 |ddv_scf|^2 =  0.313E+15
> > 
> > 
> > 
> > 
> > And the output for a q-point away from Gamma:
> > 
> > 
> > Computing dynamical matrix for.
> >                     q = (   0.1443376   0.2500000   0.0000000 )
> > 
> > 
> >       2 Sym.Ops. (no q -> -q+G )
> > //
> >  Atomic displacements:
> >      There are  63 irreducible representations
> > //
> > Representation #  1 mode #   1
> >      
> >      Self-consistent Calculation
> > 
> > 
> >       iter #   1 total cpu time :  1117.1 secs   av.it.:   5.8
> >       thresh= 0.100E-01 alpha_mix =  0.150 |ddv_scf|^2 =  0.315E-04
> > //
> >       iter #  15 total cpu time :  2442.8 secs   av.it.:  10.2
> >       thresh= 0.105E-06 alpha_mix =  0.150 |ddv_scf|^2 =  0.454E-12
> > 
> > 
> > 
> > 
> > 
> > 
> > Some info on the self-consistent calculation before:
> > 
> > 
> > occupations='smearing', smearing='methfessel-paxton', degauss=0.01
> > ecutwfc = 38.0, ecutrho = 304.0,
> > conv_thr =  1.0d-10
> > K_POINTS {automatic}: 12 12 1 0 0 0
> > nat= 21, ntyp= 1
> > CELL_PARAMETERS {hexagonal}
> > 0.86602540    -0.5000000   0.000000
> > 0.86602540    0.50000000   0.000000
> > 0.00000000    0.00000000   25.71450
> > 
> > 
> > 
> > 
> > 
> > 
> > -------------------------------------------------------------
> > Nicki Frank Hinsche, Dr. rer. nat.
> > Institute of physics - Theoretical physics,
> > Martin-Luther-University Halle-Wittenberg,
> > Von-Seckendorff-Platz 1, Room 1.07
> > D-06120 Halle/Saale, Germany
> > Tel.: ++49 345 5525460
> > -------------------------------------------------------------
> > 
> > _______________________________________________
> > Pw_forum mailing list
> > Pw_forum at pwscf.org
> > http://pwscf.org/mailman/listinfo/pw_forum

-- 
 Paolo Giannozzi, Dept. Chemistry&Physics&Environment, 
 Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
 Phone +39-0432-558216, fax +39-0432-558222