software to fit optical spectra - Quantum Materials Group

2 f
The model for ε d [cm] -
y
3 f
The model for ε z
- -
4 The model for ε - -
5 s
The model for ε y
- -
6 s
The model for ε z
- -
s
x
Table 4-11 The parameters of the model “Ellipsometry of an orthorhombic film on an orthorhombic substrate”.
An example of such a model is shown in Figure 4-11. It is assumed that the “Model2”,
“Model3” and “Model4” describe the x, y and z components respectively of the film dielectric
tensor. The substrate is uniaxial with the symmetry axis z, normal to the sample surface. The x-
and y-components of the substrate dielectric tensor are described by the “Model5”, the zcomponent
is given by the “Model6”. The angle of incidence is 70 o , the angle of polarizer is
45 o and the film thickness 0.000532 cm (5.32 micron).
Figure 4-11 An example of the model “Ellipsometry of an orthorhombic film on an orthorhombic substrate”.
4.7.6. Extended Drude
This model takes as an input a dielectric function ε (ω)
given by some dielectric function
model and converts it to the frequency-dependent scattering rate 1/ τ ( ω)
and the normalized
*
frequency-dependent effective mass m ( ω ) / m according to the formulas:
2
1 ω p ⎛ 1 ⎞
= − Im ⎜
⎟ , ∞
τ ( ω)
ω ⎝ ε ( ω)
− ε ⎠
*
m ( ω)
m
2
ω p ⎛ 1 ⎞
− Re ⎜
⎟ .
2
ω ⎝ ε ( ω)
− ε ⎠
= ∞
Guide to RefFIT Page 70