[Pw_forum] charge transfer in GaAs from projwfc

[G.Autes]

Hi

I am trying to calculate the local charge in GaAs.
I did a self consistent calculation for bulk GaAs which gave me the correct bands structure (for the valence bands).
Then I tried to calculate the local DOS and charge on each atom using projwfc.x.

I obtain these Lowdin charges (atom 1 is Ga and 2 is As):

>   Lowdin Charges:
>
>     Atom #   1: total charge =   2.9724, s =  1.0494, p =  1.9231,
>     Atom #   2: total charge =   4.9937, s =  1.3894, p =  3.6043,
>     Spilling Parameter:   0.0042

which are the integer charge of the atoms...
But we should expect a charge transfer from Ga to As.
D. Sanchez-Portal et al. (Solid State Com. 95 685), using the same method, report a charge transfer of 0.42eV  in GaAs.

I include my input files. Could you tell me if I'm missing something?

Thanks

--
Gabriel Autes
Open University, Milton-Keynes, UK
City University, London, UK

-----------------------------------
input file for the scf calculation:

&control
  calculation='scf',
  outdir='./tmp',
  prefix='gaas',
  pseudo_dir='/home/gautes/Progs/espresso-4.0.4/pseudo'
/

&system
  ibrav=2,
  celldm(1)=10.6827,
  nbnd=8,
  nat=2,
  ntyp=2,
  ecutwfc=40.0d0,
  occupations='fixed',
  nspin=1
/

&electrons
  conv_thr=1d-6,
  mixing_beta=0.7,
  diagonalization='david'
/

ATOMIC_SPECIES
 Ga   69.723   Ga.pz-bhs.UPF
 As   74.92160 As.pz-bhs.UPF

ATOMIC_POSITIONS  alat
  Ga 0.0   0.0   0.0
  As 0.25  0.25  0.25

K_POINTS   automatic
   10 10 10 0 0 0


----------------------------------------
input file for projwfc.x:

&INPUTPP
  prefix='gaas',
  outdir='./tmp',
  Emin=-10.0,
  Emax= 20.0,
  DeltaE=0.05,
  filpdos="gaas",
  filproj="proj.dat"
  ngauss=0
/

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