ternary-wz-default
Ternary wurtzite parameters
Parameters for wurtzite type ternary alloys. This parameter set refers to the
binary constituents and their material parameters and specifies the bowing
parameters for interpolation between the binaries.
Please check the Database section for more details:
$ternary-wz-default
Bowing parameters b are defined for
Q[AxB1-xC] = x * Q[AC] + (1-x) * Q[BC] - b
* x * (1-x).
b is defined as b = 4Q(A0.5B0.5C) -
2[ Q[AC] + Q[BC] ].
The advantage of the bowing model is that it requires knowledge of the
relevant quantity only at a composition x=0.5 together with the values for the
binaries.
!-----------------------------------------------------------------!
$ternary-wz-default
optional !
ternary-type
character
required ! Al(x)Ga(1-x)N-wz-default, must be
a declared binary material
ternary-name
character
optional !
apply-to-material-numbers
integer_array required !
binary(x)
character
optional ! AlN-wz-default, must be a defined binary material
binary(1-x)
character
optional ! GaN-wz-default, must be a defined binary material
!
bow-conduction-band-masses
double_array
optional ! Bowing parameters b are
defined for Q[A(x)B(1-x)C] = x*Q[AC]+(1-x)*Q[BC]-b*x*(1-x)
bow-conduction-band-nonparabolicities
double_array
optional ! [m0]
bow-conduction-band-energies
double_array
optional !
!
bow-valence-band-masses
double_array
optional ! [m0]
bow-valence-band-nonparabolicities
double_array
optional !
bow-valence-band-energies
double_array
optional ! "average" valence band edge energy
Ev (see comments below)
!
band-shift
double
optional ! to adjust band alignments (should
be zero in database)
bow-band-shift
double
optional ! to adjust band alignments, using
band shifts specified for binaries
!
bow-abs-deformation-pot-vb
double
optional ! not used in wurtzite
bow-abs-deformation-pots-cbs
double_array
optional ! bow absolute deformation
potentials of conduction band minima: a_cd , a_ci [eV]
bow-uniax-vb-deformation-pots
double_array
optional ! b,d related
bow-uniax-cb-deformation-pots
double_array
optional !
!
bow-lattice-constants
double_array
optional !
bow-elastic-constants
double_array
optional !
bow-piezo-electric-constants
double_array
optional !
bow-pyro-polarization
double_array
optional !
!
bow-static-dielectric-constants
double_array
optional !
bow-optical-dielectric-constant
double
optional !
!
bow-6x6kp-parameters
double_array
optional !
bow-8x8kp-parameters
double_array
optional !
!
bow-LO-phonon-energy
double
required !
!
$end_ternary-wz-default
optional !
!-----------------------------------------------------------------!
Syntax
ternary-type = character
=
Al(x)Ga(1-x)N-wz-default
=
Al(x)In(1-x)N-wz-default
=
In(x)Ga(1-x)N-wz-default
If the string is a known material-type, the default parameters for this
material type will be read from the database first. By specifying some of the
parameters by the present keyword and specifiers, the defaults will be
overwritten.
If the string is not known to the database, you will be prompted for
all of the material parameters. In this case you have to specify the relevant
specifiers in
$material (material-model,
material-type). If here a known material-type is specified,
however, then not all material parameters are needed as the defaults are taken
unless otherwise specified. See here for an example:
$material
The binary
constituents can still be either known or unknown binary materials.
ternary-name = string
String is a name of your choice.
apply-to-material-numbers = num1 num2 ...
Intended to change only some parameters for some materials which are otherwise
identical.
binary(x) = string
String can be either a known binary or an arbitrary name. In case this binary is
not a known material, you will be prompted for all material parameters. In its
current implementation, there are only a few checks with respect to the number
of data expected for each parameter. Most likely, the program will simply crash
if something is specified which differs from the data structure of a known
material.
binary(1-x) = string
The name of the second binary for the alloy. Limitations and problems as for the
other binary.
bow-conduction-band-masses = 0d0 0d0 0d0 ! [m0]
masses at the Gamma point m_|_, m_|_, m||
(with respect to c-axis)
0d0 0d0 0d0 ! [m0]
0d0 0d0 0d0 ! [m0]
For each set of degenerate minima a triplet of bowing parameters for the three
masses associated to the minimum.
bow-conduction-band-nonparabolicities = double1 double2 ...
Bowing parameters for the nonparabolicity parameters in the conduction band
minima. One nonparabolicity parameter for each set of degenerate minima.
bow-conduction-band-energies = double1 double2 ...
Bowing parameters for conduction band energies. One bowing parameter for each
set of degenerate minima.
bow-valence-band-masses = 0d0 0d0 0d0 !
[m0] heavy hole (HH) masses m_|_, m_|_, m||
(with respect to c-axis)
0d0 0d0 0d0 ! [m0]
light hole (LH) masses m_|_, m_|_, m||
(with respect to c-axis)
0d0 0d0 0d0 !
[m0]
bow-valence-band-nonparabolicities = ...
bow-valence-band-energies = ...
The "average" valence band edge energy is according to Ev in:
S.L. Chuang, C.S. Chang
k.p method for strained wurtzite semiconductors
Phys. Rev. B 54 (4), 2491 (1996)
The "average" valence band energy Ev is defined on an absolute
energy scale and must take into accout the valence band offsets which are "averaged" over the three holes.
Note: The real average of the three holes is: Ev,av =
(EHH + ELH + ECH ) / 3 = Ev + 2/3 Deltacr
band-shift = double
Can be used to rigidly shift the band energies.
bow-band-shift = double
Bowing parameter to interpolate rigid band shift of binaries.
bow-abs-deformation-pot-vb = double ! a_v [eV]
- not used in wurtzite
Bowing parameter for absolute deformation potential of valence bands.
bow-abs-deformation-pots-cbs = a2 a2
a1
Bowing parameters for absolute deformation potentials of Gamma conduction band
minima a_c (a axis),
a_c (a axis),
a_c (c axis)
bow-uniax-vb-deformation-pots = double1
...
Bowing parameters for uniaxial deformation potentials of valence bands.
bow-uniax-cb-deformation-pots = double1
...
Bowing parameters for uniaxial deformation potentials of conduction bands.
Xi_u (at minimum)
bow-lattice-constants = double1 double2 double3
Bowing parameters for lattice constants.
bow-piezo-electric-constants = double1 double2 double3
Bowing parameters for piezoelectric constants e33, e31, e15.
bow-elastic-constants = double1 double2 double3
Bowing parameters for elastic constants C11,C12,C13,C33,C44.
bow-pyro-polarization = 0 0 bow-Psp ! [C/m2]
Bowing parameters for components of spontaneous pyroelectric polarization.
bow-static-dielectric-constants = double1 double2 double3
Bowing parameters for static dielectric constants.
bow-optical-dielectric-constant = double
Bowing for high frequency dielectric constant.
bow-6x6kp-parameters = A1 A2 A3
! 6x6 k.p Rashba-Sheka-Pikus
parameters
A4 A5 A6
!
Delta1 Delta2 Delta3 ! [eV]
Bowing parameters for 6x6 k.p model.
bow-8x8kp-parameters = A1' A2' A3'
! 8x8 k.p Rashba-Sheka-Pikus
parameters
A4' A5' A6' !
B1 B2 B3
! [hbar2/(2m0)]
old version: P1
P2 !
[eVAngstrom]
E_P1 E_P2 !
[eV]
S1 S2 !
[]
Bowing parameters for 8x8 k.p model.
A1,A2,A3,A4,A5,A6:
6x6 (or 8x8) Rashba-Sheka-Pikus k.p parameters for wurtzite
Delta1: [eV]
Delta2 = Delta3 = 1/3 Delta_so [eV]
Delta_so: spin-orbit split-off energy [eV)]
B1,B2,B3:
8x8 k.p inversion symmetry parameters in units of [hbar2/(2m0)]
old version: P1,P2: momentum
matrix element parameters derived from Kane's momentum matrix elements Ep1,
Ep2 in units of [eVAngstrom]
E_P1,E_P2: Kane's momentum matrix elements EP1,
EP2 in units of [eV]
S1,S2: 8x8
k.p parameters for the conduction band mass (dimensionless)
Note: The S
parameter is also defined in the literature as F
where S = 1 + 2F, e.g. I. Vurgaftman et al., JAP 89,
5815 (2001).
Consequently, the bowing parameter for S
has the value 2 * F.
bow-LO-phonon-energy = 0d0
! [eV] low-temperature optical phonon energy
Please check the Database section for more details:
$ternary-wz-default
| 
