Dear Siesta users,

 

Recently, I'm trying to  calculate the band structure of monolayer MoSe2.
However, when I plotting the bands, the band curves at K point are not at
maximum or minimum, which should be. And there seems a non-differential
point at K along the bands. The band structure of MoSe2 is attached, the
non-differential point is more obvious at the lowest two bands shown in the
Fig. Both LDA and PBE functionals give this strange phenomenon. I have tried
to tune many parameters, but failed to get good result. Can anyone help me
with the problem? 

By the way, I have tried pseudopotentials from Siesta website and from
http://charter.cnf.cornell.edu/, and also used the recently published pps of
Comput. Mater. Sci. , 98 (2015) 372-389. I also changed the energshift,
meshcutoff, and k point mesh. But none of them can resolve the problem.
Below are the input files for relaxation and band structure calculations.
Any comment or advice are highly appreciated.

 

 

fdf for relaxation:

 

# General System Descriptors

 

SystemName              mose2

SystemLabel             mose2

 

NumberOfAtoms           3

NumberOfSpecies         2

 

%block ChemicalSpeciesLabel

1  42  Mo

2  34  Se

%endblock ChemicalSpeciesLabel

 

PAO.EnergyShift         50 meV

PAO.BasisSize           DZP

 

# Structure and K-sampling

 

LatticeConstant         1.00 Ang

%block LatticeParameters

3.25 3.25 20.00 90. 90. 120.

%endblock LatticeParameters

 

AtomicCoordinatesFormat Fractional

AtomicCoorFormatOut     Ang

%block AtomicCoordinatesAndAtomicSpecies

       0.333333333   0.666666670   0.505669950  1

       0.666666667   0.333333330   0.625537344  2

       0.666666667   0.333333330   0.385811946  2

%endblock AtomicCoordinatesAndAtomicSpecies

 

%block kgrid_Monkhorst_Pack

  12  0  0  0.5

   0 12  0  0.5

   0  0  1  0.0

%endblock kgrid_Monkhorst_Pack

 

# DFT

 

XC.functional           LDA

XC.authors              CA

SpinPolarized           false

MaxSCFIterations        200     

DM.MixingWeight         0.25

DM.NumberPulay          3

DM.Tolerance            1.d-5

MeshCutoff              300 Ry

SolutionMethod          diagon

ElectronicTemperature   300.0 K

 

# MD and Relaxations

 

MD.TypeOfRun            CG

MD.VariableCell         T

MD.MaxForceTol          0.01 eV/Ang

MD.MaxStressTol         0.1 GPa

MD.NumCGsteps           200

MD.MaxCGDispl           0.1 Ang

MD.RelaxCellOnly        F

 

%block GeometryConstraints

   stress 3 4 5 6

%endblock GeometryConstraints

 

# Output options

 

WriteCoorInitial        true

WriteCoorStep           true

WriteForces             true

WriteKpoints            false

WriteEigenvalues        false

WriteKbands             false

WriteBands              false

WriteMullikenPop        0

WriteWaveFunction       false

WriteCoorXmol           true

WriteCoorCerius         false

WriteMDCoorXmol         true

WriteMDhistory          true

WriteMDXmol             true

WriteDM                 true

 

fdf for band structure:

# General System Descriptors

 

SystemName             mose2

SystemLabel             mose2

 

NumberOfAtoms           3

NumberOfSpecies         2

%block ChemicalSpeciesLabel

1  42  Mo

2  34  Se

%endblock ChemicalSpeciesLabel

 

PAO.BasisSize           DZP

PAO.EnergyShift         50 meV

 

# Structure and K-sampling

 

LatticeConstant         1.00 Ang

%block LatticeParameters

3.16 3.16 13.00 90. 90. 120.

%endblock LatticeParameters

 

AtomicCoordinatesFormat Fractional

AtomicCoorFormatOut     Ang

%block AtomicCoordinatesAndAtomicSpecies

       0.333333333   0.666666670   0.505669950  1

       0.666666667   0.333333330   0.625537344  2

       0.666666667   0.333333330   0.385811946  2

%endblock AtomicCoordinatesAndAtomicSpecies

 

%block kgrid_Monkhorst_Pack

  24  0  0  0.5

   0 24  0  0.5

   0  0  1  0.0

%endblock kgrid_Monkhorst_Pack

 

# DFT

 

XC.functional           LDA

XC.authors              CA

SpinPolarized           false

MaxSCFIterations        200     

DM.MixingWeight         0.25

DM.NumberPulay          3

DM.Tolerance            1.d-5

MeshCutoff              300 Ry

SolutionMethod          diagon

ElectronicTemperature   300.0 K

 

# Output options

 

WriteCoorInitial        true

WriteCoorStep           true

WriteForces             true

WriteKpoints            false

WriteEigenvalues        false

WriteKbands             false

WriteBands              false

WriteMullikenPop        0

WriteWaveFunction       false

WriteCoorXmol           true

WriteCoorCerius         false

WriteMDCoorXmol         true

WriteMDhistory          true

WriteMDXmol             true

WriteDM                 true

UseStructFile           T

 

BandLinesScale ReciprocalLatticeVectors

 

%block BandLines

1   0.0000  0.0000 0.0000  \Gamma

70  0.0000  0.5000 0.0000  M

40  0.3333  0.3333 0.0000  K

80  0.0000  0.0000 0.0000  \Gamma

%endblock BandLines

 

 

 

 

Best regards,

 

Xiaoming Wang

IAMDN, Rutgers

Attachment: Band structure of MoSe2.pdf
Description: Adobe PDF document

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