threshold_delta1
Calling sequence
classical{ threshold_delta1 = ... }
Properties
usage: \(\mathrm{\textcolor{ForestGreen}{optional}}\)
type: real number
values: no constraints
default: \(r=0.0\)
unit: \(\mathrm{eV}\)
Functionality
When alloying wurtzite AlN with other wurtzite III-V binary compounds then the character of some valence bands changes gradually with the content of the alloy without any band crossings. It happens due to the change of the sign of \(\Delta_1\) parameter. Classification of bands as HH, LH, or SO using analytical formulas is insufficient in this case, resulting in an artificial abrupt changes of the character of the bands, swapping. Further it may result in an artificial resonance observed in the densities of holes.
This keyword allows to move the swapping to a different alloy content.
Hint
If moving the artifact out of regions with holes is impossible, then it is advised to tune this keyword such that the swapping artifact overlaps with the crossing of other valence bands. It does not remove the artifact, but we have noticed that it notably reduces it’s magnitude.
Attention
This is only relevant for semi-classical simulations, where classification of bands impacts assignment of effective masses. If one uses 6-band or 8-band \(\mathbf{k} \cdot \mathbf{p}\) models and densities obtained from solutions of the Schrödinger equation, then this problem is only present in the output of the band profiles, hance can be completely ignored.
threshold_delta2
Calling sequence
classical{ threshold_delta2 = ... }
Properties
usage: \(\mathrm{\textcolor{ForestGreen}{optional}}\)
type: real number
values: no constraints
default: \(r=0.0\)
unit: \(\mathrm{eV}\)
Functionality
When alloying wurtzite ZnO with other wurtzite II-VI binary compounds then the character of some valence bands changes gradually with the content of the alloy without any band crossings. It happens due to the change of the sign of \(\Delta_2\) parameter. Classification of bands as HH, LH, or SO using analytical formulas is insufficient in this case, resulting in an artificial abrupt changes of the character of the bands, swapping. Further it may result in an artificial resonance observed in the densities of holes.
This keyword allows to move the swapping to a different alloy content.
Hint
If moving the artifact out of regions with holes is impossible, then it is advised to tune this keyword such that the swapping artifact overlaps with the crossing of other valence bands. It does not remove the artifact, but we have noticed that it notably reduces it’s magnitude.
Attention
This is only relevant for semi-classical simulations, where classification of bands impacts assignment of effective masses. If one uses 6-band or 8-band \(\mathbf{k} \cdot \mathbf{p}\) models and densities obtained from solutions of the Schrödinger equation, then this problem is only present in the output of the band profiles, hance can be completely ignored.
Last update: 2025-09-09