[Pw_forum] Negative charge !

[Von Braun Nascimento]

Dear all,  

I am trying to generate some charge plots for a prototype bulk La/Sr
manganite. 
The 1-D charge plot along Sr-O atoms is negative close to the Sr core,
although it does not happen along La-O atoms. I've checked PW forum archives
and there is a comment about increasing the number of k points or the
cut-off energy.  I've increased both (see attached input files) and nothing
has changed so far. Why do this negative charge problem is present only
close to Sr ? 
Thanks in advance. 

Regards, Von  



============================================================================
=========
PWSCF input file :

 &control
    calculation='scf'
    restart_mode='from_scratch',
    pseudo_dir = '/home/von/Mang-DFT/BULK/',
    outdir='/home/von/Mang-DFT/BULK/tmp/'
    prefix='Mang-scf'
    tstress = .true.
    tprnfor = .true.
 /
 &system
    ibrav = 6, celldm(1) =  7.323629, celldm(3)= 5.199886,nat= 24, ntyp= 4,
    ecutwfc =  30.0, ecutrho = 300.0
    occupations='smearing', smearing='methfessel-paxton', degauss=0.02  /
&electrons
    diagonalization='david'
    conv_thr = 1.0e-8
    mixing_beta = 0.7
 /
ATOMIC_SPECIES
 O    15.9994     O.pbe-van_ak.UPF
Mn    54.938045   Mn.pbe-sp-van.UPF
La   138.90547    La.pbe-nsp-van.UPF
Sr    87.62       Sr.pbe-nsp-van.UPF
ATOMIC_POSITIONS
O      0.50000  0.50000   0.00000
La     0.00000  0.00000   0.06947
Mn     0.50000  0.50000   0.51723
O      0.50000  0.00000   0.52373
O      0.00000  0.50000   0.52373
O      0.50000  0.50000   1.01850
La     0.00000  0.00000   1.01850
Mn     0.50000  0.50000   1.51977
O      0.50000  0.00000   1.51327
O      0.00000  0.50000   1.51327
O      0.50000  0.50000   2.03700
La     0.00000  0.00000   1.96753
O      0.00000  0.00000   2.59994
Sr     0.50000  0.50000   2.66941
Mn     0.00000  0.00000   3.11718
O      0.50000  0.00000   3.12368
O      0.00000  0.50000   3.12368
O      0.00000  0.00000   3.61844
Sr     0.50000  0.50000   3.61844
Mn     0.00000  0.00000   4.11971
O      0.50000  0.00000   4.11321
O      0.00000  0.50000   4.11321
O      0.00000  0.00000   4.63695
Sr     0.50000  0.50000   4.56748
K_POINTS (automatic)
 13 13 13 0 0 0

===========================================================================
PP input file :

 &inputpp
    prefix  = 'Mang-scf'
    outdir = '/home/von/Mang-DFT/BULK/tmp/'
    filplot = 'Mangcharge'
    plot_num= 0
 /
 &plot
    nfile = 1
    filepp(1) = 'Mangcharge'
    weight(1) = 1.0
    iflag = 1
    output_format = 0
    fileout = 'Sr-Oplane.dat'
    e1(1) =  0.00000, e1(2) =-0.50000, e1(3) = -0.45426,
    x0(1) = 0.50000, x0(2)= 0.50000, x0(3) = 4.56748,
    nx=   100
 /

============================================

         Dr. Von Braun Nascimento

        Pos-doc Research Associate

       Dept of Physics and Astronomy
         University of Tennessee
                    & 
  Materials Science and Technology Division
       Oak Ridge National Laboratory 

============================================