Example: Effective Mass (electron mobility)¶

#! /bin/sh

# An effective mass calculation is about the curvature of band at the top of the
# valence band and the bottom of the conduction band. This is obtained by
# numerical differentiation.

# It can be done for systems with 1D, 2D, or 3D translational symmetry.

# The easiest way to use this feature is to specify an empty EffectiveMass key
# block (so leave out the NumAbove, NumBelow, and UniqueKPoints).

# == Example 1D ==

echo "example 1D"

AMS_JOBNAME=EffectiveMass1D $AMSBIN/ams <<eor

Task SinglePoint 

System
  Atoms
     Al 0.0 0.0 0.0
  END
  Lattice
     2.12440502 0.0 0.0
  End
End

Engine Band
  TITLE 1D Al Chain

  EffectiveMass
    Enabled True
    KPointCoord -0.783
    StepSize 0.001
    NumAbove 4
    NumBelow 2
  End

  Basis
     Type DZ
     Core Large
  End
EndEngine
eor


# == Example 2D ==

echo "example 2D"

AMS_JOBNAME=EffectiveMass2D $AMSBIN/ams <<eor

Task SinglePoint 

System
  Atoms 
     Mo     -1.626960686     0.313108730     0.000000000
     S       0.000000000     1.252434919     1.547040825
     S       0.000000000     1.252434919    -1.547040825
  End

  Lattice
     1.626960686    -2.817978569     0.000000000
     1.626960686     2.817978569     0.000000000
  End
End

Engine Band
  TITLE MoS2Slab

  EffectiveMass
    Enabled True
  End

  Basis
     Type DZ
     Core Large
  End
EndEngine

eor

# == Example 3D ==

echo "example 3D"

AMS_JOBNAME=EffectiveMass3D $AMSBIN/ams <<eor

Task SinglePoint 
System
  Atoms
     Zn  1.625 0.9381941876 0.0
     Zn  1.625 -0.9381941878 2.615
     O   1.625 0.9381941876 1.96125
     O   1.625 -0.9381941878 4.57625
  END
  Lattice
     1.625 -2.814582562 0.000000
     1.625 2.814582562 0.000000
     0.000000 0.000000 5.23
  End
End

Engine Band
  TITLE ZnO

  NumericalQuality Basic

  KSpace
    Quality Normal
  End
  tails bas=1e-8

  EffectiveMass
    Enabled True
    NumAbove 1
    NumBelow 1
  End

  Basis
     Type DZ
     Core Large
  End
EndEngine

eor