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Difference between revisions of "Plotting the BSE fatband structure of Si"

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== Calculation ==  
 
== Calculation ==  
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 +
*In this example we will calculate and plot the first "bright" BSE eigenstate of silicon. In this tutorial the modelBSE setup from the previous tutorial is used in combination with a <math>10 \times 10 \times 10</math> gamma centered k-point grid (if you don't want to wait that long, a <math> 4 \times 4 \times 4</math> grid takes only a minute). In principle the standard BSE method can also be used instead.
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*The {{TAG|INCAR}} file for the modelBSE calculation looks like the following:
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{{TAGBL|System}}  = Si
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 +
{{TAGBL|PREC}} = Normal ; {{TAGBL|ENCUT}} = 250.0
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#{{TAGBL|ALGO}} = BSE
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{{TAGBL|ANTIRES}} = 0
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{{TAGBL|ISMEAR}} = 0 ; {{TAGBL|SIGMA}} = 0.01
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{{TAGBL|ENCUTGW}} = 150
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{{TAGBL|EDIFF}} = 1.E-8 # default 1.E-4
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{{TAGBL|NBANDS}} = 16  # only bands that are used are required, prepare the same set in a forgoing DFT run
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{{TAGBL|NBANDSO}} = 4
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{{TAGBL|NBANDSV}} = 8
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{{TAGBL|OMEGAMAX}} = 20
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{{TAGBL|PRECFOCK}} = Normal
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{{TAGBL|ALGO}} = TDHF
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{{TAGBL|LMODELHF}} = .TRUE. #Turn model on
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{{TAGBL|HFSCREEN}} = 1.26  # Screening lenght
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{{TAGBL|AEXX}} = 0.088    #Inverse of epsilon_infinity
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{{TAGBL|SCISSOR}} = 0.69  # Difference GW-DFT band gap
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{{TAGBL|NBSEEIG}} = 10 # number of BSE eigenvectors written out in {{TAGBL|BSEFATBAND}}
  
 
== Download ==
 
== Download ==

Revision as of 11:51, 14 December 2017

Task

Visualization of BSE eigenvectors using fatbands.

Input

Si
 5.4300
0.5 0.5 0.0
0.0 0.5 0.5
0.5 0.0 0.5
2
cart
0.00 0.00 0.00 
0.25 0.25 0.25 

INCAR

  • This is the INCAR file for the basic DFT calculation:
System  = Si

PREC = Normal ; ENCUT = 250.0

ISMEAR = 0 ; SIGMA = 0.01
KPAR = 2

EDIFF = 1.E-8
NBANDS = 16
LOPTICS = .TRUE.  # needed for WAVEDER file
LPEAD = .TRUE.
OMEGAMAX = 40

KPOINTS

The KPOINTS file will be automatically generated in this example.


Calculation

  • In this example we will calculate and plot the first "bright" BSE eigenstate of silicon. In this tutorial the modelBSE setup from the previous tutorial is used in combination with a gamma centered k-point grid (if you don't want to wait that long, a grid takes only a minute). In principle the standard BSE method can also be used instead.
  • The INCAR file for the modelBSE calculation looks like the following:
System  = Si

PREC = Normal ; ENCUT = 250.0

#ALGO = BSE 
ANTIRES = 0
ISMEAR = 0 ; SIGMA = 0.01
ENCUTGW = 150

EDIFF = 1.E-8 # default 1.E-4
NBANDS = 16   # only bands that are used are required, prepare the same set in a forgoing DFT run
NBANDSO = 4
NBANDSV = 8
OMEGAMAX = 20

PRECFOCK = Normal

ALGO = TDHF
LMODELHF = .TRUE. #Turn model on 
HFSCREEN = 1.26  # Screening lenght
AEXX = 0.088    #Inverse of epsilon_infinity
SCISSOR = 0.69  # Difference GW-DFT band gap

NBSEEIG = 10 # number of BSE eigenvectors written out in BSEFATBAND

Download

Si_improve_eps.tgz

References

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