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nextnano≥ software







Assigns a material to a region cluster. For unknown materials that are not know to the database, see below.

$material                                      required  ! specifications, to assign material to regions
 material-number               integer         required  ! an integer number to refer to a specific material
 cluster-numbers               integer_array   required  ! assign material to these region numbers
 material-name                 character       required  ! GaAs, Al(x)Ga(1-x)As, Si(x)Ge(1-x), ...
 alloy-function                character       optional  ! constant, function
 material-model                character       optional  !
 material-type                 character       optional  ! GaAs, Al(x)Ga(1-x)As, Si(x)Ge(1-x), ...
 growth-coordinate-axis        integer_array   optional  ! must be specified if strain related quantities have to be considered
 pseudomorphic-on              character       optional  ! a default material or user defined name
 alloy-concentration           double          optional  ! in case the material is a ternary
 lattice-constants             double_array    optional  !
 lattice-constants-temp-coeff  double_array    optional  !
 crystal-type                  character       optional  ! required for nondefault substrate material: either wurtzite or zincblende
 pressure                      double          optional  !
$end_material                                  required  !


material-number = integer
integer .... integer number

cluster-numbers = int1 int2 int3 ...
int1, int2, ... integer numbers referring to existent region cluster numbers

material-name = character
Either a known material name or an arbitrary string of length < 89. For unknown material names, the material-model which fixes the data structure expected must be specified.


alloy-function = constant
 = linear
               = ...
The name of a known alloy function - fixes the function used to generate the alloy profile within the material.
For known function names please have a look here: $known-functions-names and $alloy-function.


These two specifiers are needed if the material is completely unknown to database.

  • material-model = binary-zb-default  ! zinc blende
     = ternary-zb-default !
    zinc blende
     = binary-wz-default  !
     = ternary-wz-default ! wurtzite
  • material-type  = character
    The name of a material dataset. Known sets are (among others, see database):
    GaAs-zb-default, AlAs-zb-default, Si-zb-default, Ge-zb-default, Al(x)Ga(1-x)As-zb-default, In(x)Ga(1-x)As-zb-default, Si(1-x)Ge(x)-zb-default, GaN-wz-default, AlN-wz-default, Al(x)Ga(1-x)N-wz-default, ...

 material-number = 5
 material-name   = Electrolyte
 cluster-numbers = 5
 material-model  = binary-wz-default      !
is necessary if "Electrolyte" is not known to database
 material-type   = Electrolyte-wz-default

 material-number = 6 !


growth-coordinate-axis = 1 0 0 ! along x axis defined in simulation coordinate system
                       = 0 1 0 !
along y axis defined in simulation coordinate system
                       = 0 0 1 !
along z axis defined in simulation coordinate system
Selects one of the simulation coordinate axes as the growth direction. Which crystal direction this corresponds to is fixed by the orientation of the crystal with respect to the simulation coordinate system.

pseudomorphic-on = GaAs
String is either a material name known by the database or an arbitrary string referring to some material. In the latter case, lattice constants and crystal type have to be provided by the input.

alloy-concentration = xalloy
If pseudomorphic-on refers to an alloy, the alloy composition xalloy must be specified.


lattice-constants = a1 a2 a3
Three numbers for zinc blende or wurtzite. In case of zinc blende a1=a2=a3, for wurtzite a1=a2 and arbitrary a3.

lattice-constants-temp-coeff = 3.88d-6  3.88d-6  3.88d-6  ! [nm/K]
More information on temperature dependent lattice constants...

pressure     = 9.4        ! [GPa]
The material could be strained by an additional external pressure.


crystal-type = zincblende
 = wurtzite


Unknown materials

For totally unknown materials, all parameters must be specified in the input file.



 material-number = 1
 material-name   = SiN                !
new material name
 material-model  = binary-wz-default  !
material-model of new material (wurtzite, binary)
 material-type   = SiN-wz-default     !
material-type of new material
 cluster-numbers = 1

 material-number = 2


$binary-wz-default                          ! (wurtzite, binary)
binary-type               = SiN-wz-default !
Parameters of new material
 apply-to-material-numbers = 1
 conduction-bands          = 3
 conduction-band-masses    = 0.0795d0 0.0795d0 0.0795d0

See also:
- $binary-zb-default
- $binary-wz-default
- $
- $