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[<fishzhou@gmail.com>]

Hi there,

I'm using LDA to calculate the band structure of 1-layer graphene sheet. but I
get a NON-ZERO energy gap (about 0.3eV) at kpoint "K", which doesn't agree 
with
other results. Could any one please tell me what's going on?

Thanks a lot

Aaron

=======================input file=================
ndtset 2

# Dataset 1 : usual self-consistent calculation for ground state charge 
density
kptopt1   1
ngkpt1    12 12 1
nshiftk1  4
shiftk1   0.0 0.0 0.0
          0.5 0.5 0.0
          0.0 0.5 0.0
          0.5 0.0 0.0

toldfe1  1.0d-7
prtden1  1
nband1   32

######################################################
# Dataset 2: calculation of kss file
kptopt2   -3
nband2    10
ndivk2    20 20 20

kptbounds2   0.6666666666667 0.333333 0.0
             0.0 0.0 0.0
             0.5 0.0 0.0
             0.6666666666667 0.333333 0.0

getden2   -1
iscf2     -2
tolwfr2   1.0d-12
enunit2   1

# Definition of the unit cell
acell  4.6384188886E+00  4.0166196155E+00  2.8345891875E+01 
rprim  1.0  0.0  0.0
       0.5  1.0  0.0
       0.0  0.0  1.0

# Definition of the atom types
ntypat 1
znucl  6

# Definition of the atoms
natom  2              # total Number of ATOMs in the unit cell
typat  2*1            # TYPE of atoms
xangst
  -1.4377960534E-21  2.0000000000E-05  0.0000000000E+00
   1.2272700000E+00  7.0848000000E-01  0.0000000000E+00

ecut 16.0         # Maximal kinetic energy cut-off, in Hartree
nstep   200       # Maximal number of SCF cycles
diemac  4.0       # model DIElectric MACroscopic constant
symmorphi 0       # must 0 for GW, default 1
timopt -1          # TIMing OPTion, -1 a full analysis of timings