$negfionizedimpurity

$negfionizedimpurity is the command to setup the related parameters of ionized impurity scattering.
The equation of ionized impurity scattering:

 $W_{imp}(k)=4\pi F(\frac{2k}{\lambda})^{2}[\frac{1}{\sin^2(\frac{\theta}{2})+(\frac{\lambda}{2k})^2}]^{2}$

 $F=\frac{1}{\hbar}[\frac{}{}]^{2}$