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[tianmiao8287@163.com]

dear sir,
    Last question(BaVSe3  band  gap) is my classmate who asks instead of 
me.He don't understand my meaning.I am sorry about that.
There is a problem puzzled me for a long time.The material is 
BaV(1-x)Ti(x)S3.when x=0.8,it is a semiconductor.But the band gap I get is 
still zero,it is still metallic.I don't know why it is.By the way ,the  DOS 
still indicates that it is  metallic.The unmixing material is BaVS3,which is 
metallic.There are 10 atoms in a unit cell.The crystal structure is 
hexagonal.The space group is 194.The input file is as follows:

# Computation of the band structure.
# First, a SCF density computation, then a non-SCF band structure calculation.

ndtset 2
prtwf2 0
#Dataset 1 : usual self-consistent calculation
kptopt1 1          # Option for the automatic generation of k points,
                   # taking into account the symmetry
nshiftk1 1
shiftk1  0.0 0.0 0.5
ngkpt1  8 8 8 
prtden1  1         # Print the density, for use by dataset 2
toldfe1  1.0d-10
nband1   60
#Dataset 2 : the band structure
iscf2    -2
getden2  -1
kptopt2  -7
nband2   60
ndivk2    50 50 50 50 50 50 50   # 10, 12 and 17 divisions of the 3 segments, 
delimited
nkpt2 351                       # by 4 points.
prtvol2 10
kptbounds2  0.0 0.0 0.0
            1/3 1/3 0.0
            1/2 0.0 0.0
            0.0 0.0 0.0
            0.0 0.0 0.5
            1/3 1/3 0.5
            0.5 0.0 0.5
            0.0 0.0 0.5
tolwfr2  1.0d-16
enunit2  1             # Will output the eigenenergies in eV 

#Definition of the unit cell
acell 12.74053353 12.74053353 10.85836631      
rprim  -sqrt(0.75)  1/2  0
             0  -1    0
              0      0      1



npsp 4
ntypat 3          # There is only one type of atom
znucl 56 16 23 22                         
ntypalch 1
mixalch  0.2 0.8
algalch 1
ntyppure 2
npspalch 2
        
#Definition of the atoms
natom 10           # There are two atoms
typat 1 1 2 2 2 2 2 2 3 3        
xred       
 1/3 2/3 3/4
 2/3 1/3 1/4
 5/6 2/3 3/4
 1/3 1/6 3/4
 5/6 1/6 3/4
 2/3 5/6 1/4
 1/6 1/3 1/4
 1/6 5/6 1/4
 0.0 0.0 1/2
 0.0 0.0 0.0
occopt 1
#Definition of the planewave basis set
ecut 55         # Maximal kinetic energy cut-off, in Hartree

#Definition of the SCF procedure
nstep 300          # Maximal number of SCF cycles
diemac 12