Dear siesta developers and users
I am a newbie in band structure calculation. I calculate the band structure of
LiF, and a 2*2*2 supercell of 64 atoms is selected. In this calculation, the
local density approximation (LDA) is adopted for the exchange-correlation
functional term, the band structure is obtained along the high symmetric line
Γ->X->W->Γ, only gamma point is used for Brillouin zone sampling, more details
can be found in the input file which is attached below.
I can not understand the results of the E(k) (two figs are also attached), it
seems there are two band gaps formed in the calculation (the Fermi energy is
shifted to 0 eV), I want to know which one (gap 1 or gap 2) is the band gap in
my calculation, and how does another gap come from?
Is there anything wrong in the input file?
Please help me, any suggestion or comment is appreciated.
Sincerely
Fei Mao
University of South China, China
############################ Input file for the LiF ############################
SystemName bulk.LiF
SystemLabel bulk_LiF
NumberOfAtoms 8
NumberOfSpecies 2
%block ChemicalSpeciesLabel
1 3 Li
2 9 F
%endblock ChemicalSpeciesLabel
# basis
PAO.BasisSize DZP
PAO.EnergyShift 200 meV
LatticeConstant 4.04 Ang # Lattice constant alat
%block LatticeVectors # Lattice vectors, in units of
latticeconstant
2.0 0.0 0.0
0.0 2.0 0.0
0.0 0.0 2.0
%endblock LatticeVectors
%block SuperCell
2 0 0 0.0
0 2 0 0.0
0 0 2 0.0
%endblock SuperCell
%block kgrid_Monkhorst_Pack
1 0 0 0.0
0 1 0 0.0
0 0 1 0.0
%endblock kgrid_Monkhorst_Pack
BandLinesScale ReciprocalLatticeVectors
%block BandLines
1 0.0 0.0 0.0 # Gamma-point
20 0.5 0.0 0.5 # X-point
30 0.5 0.25 0.75 # W-point
30 0.0 0.0 0.0 # Gamma-point
%endblock BandLines
%block ProjectedDensityOfStates
-20 10 0.1 300 eV
%endblock ProjectedDensityOfStates
MeshCutoff 300.0 Ry
# SCF options
MaxSCFIterations 100 # Maximum number of SCF iter
DM.NumberPulay 3 # One Pulay every 3 iter
DM.MixingWeight 0.35 # New DM amount for next SCF cycle
DM.Tolerance 5.d-4 # Tolerance in maximum difference
SolutionMethod diagon # OrderN or Diagon
OccupationFunction FD
ElectronicTemperature 25 meV # Temp. for Fermi smearing
# exchange-correlation functional
XC.functional LDA
XC.authors CA
# structural infomation
AtomCoorFormatOut Ang
# output information
WriteCoorXmol T
WriteMDXmol T
WriteForces T
WriteKpoints .true.
WriteEigenvalues .true.
WriteKbands .true.
WriteBands .true.
WriteMullikenPop 1
# options for MD
MD.MaxForceTol 0.01 eV/Ang
MD.TypeOfRun CG
MD.NumCGSteps 400
MD.Broyden.History.Steps 6
MD.Broyden.Initial.Inverse.Jacobian 1.0
# options for continue
# MD.UseSaveCG T # neccessary!
# MD.UseSaveXV T # neccessary!
# DM.UseSaveDM true # to use continuae..ion files
AtomicCoordinatesFormat Ang
%block AtomicCoordinatesAndAtomicSpecies
-5.963747 -2.022693 -2.026392 1
-6.051639 -5.949852 -2.013945 2
-2.147364 -2.056847 -2.009531 2
-2.039835 -5.953723 -2.024337 1
-6.085698 -1.925561 2.008577 2
-5.941415 -5.910826 2.052174 1
-2.040599 -2.032355 2.028040 1
-2.129653 -6.096888 2.008118 2
%endblock AtomicCoordinatesAndAtomicSpecies
