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["Anglade Pierre-Matthieu" <anglade@gmail.com>]

Hi,

There is apparently a few problems with your input file: 
1) The energy cutoff is not converged. 
2) acell 3*11.45 is not equivalent to 3*10.217 (as stated in the comment)
3) If the material appear as a metal it is quite possible that your k-point mesh is not wide enough.
Are you working with the same pseudopotential + XC you used within vasp ? Did you tried to make converged calculations within VASP ?

regards

PMA

On Mon, Mar 31, 2008 at 4:36 AM, <wxw079000@utdallas.edu> wrote:

Dear all,

I calculated the InAs energy gap with LDA method(ABINIT 5.4.4 VERSION, PHI USPP). From my calculations, the energy gap is 0 eV whatever I changed the lattice constants, tsmear value from 0.01~0.5, kpoints (2x2x2,4x4x4,6x6x6). That's a very strange issue. On the constray, the energy gap changed when I changed the parameters above with VASP calculation. Is there any kind person to help me check the input file? The following is the input file, please check it out.

Best wishes,

Weichao,Wang

#####################
####input file ######
kptopt   1            # Option for the automatic generation of k points
ngkpt    4 4 4        # Density of k points

# Definition of the k-point grid
nkpt   10
nshiftk  4
shiftk  0.0 0.0 0.0  # This grid is the most economical
        0.5 0.0 0.0
        0.0 0.5 0.0
        0.0 0.0 0.5
prtden  1         # Print out density
acell  3*11.450        # This is equivalent to   10.217 10.217 10.217
rprim  0.0  0.5  0.5   # FCC primitive vectors (to be scaled by acell)
      0.5  0.0  0.5
      0.5  0.5  0.0

# Definition of the atom types
ntypat  2         # There is only one type of atom
znucl 49 33       # The keyword "znucl" refers to the atomic number of the
                 # possible type(s) of atom. The pseudopotential(s)
                 # mentioned in the "files" file must correspond
                 # to the type(s) of atom. Here, the only type is Silicon.

# Definition of the atoms
natom 2           # There are two atoms
typat  1 2        # They both are of type 1, that is, Silicon.
xred              # Reduced coordinate of atoms
     0.0  0.0  0.0
     0.25 0.25 0.25

# Definition of the planewave basis set (at convergence 16 Rydberg 8 Hartree)
ecut 5.0          # Maximal kinetic energy cut-off, in Hartree

# Use only symmorphic operations
symmorphi 0
 ccopt 3    # treat it as metal
 tsmear 0.01

nstep   60        # Maximal number of SCF cycles
diemac  10.00     # Although this is not mandatory, it is worth to
                 # precondition the SCF cycle. The model dielectric
                 # function used as the standard preconditioner
                 # is described in the "dielng" input variable section.
                 # Here, we follow the prescription for bulk silicon.
tolwfr  1.0d-6

# This line added when defaults were changed (v5.3) to keep the previous, old behaviour
 iscf 7
 ixc 7 7

######################################3
######################################
#########################

-- 
Pierre-Matthieu Anglade