I am confused by one question, which is very bad dielectric function fit results when I set the imaginary part is zero. How to attain better fit ?
You can change the weights for the imaginary part and give it more priority. Here is a knowledge base article on fitting the dielectric constants.
You need to go to the materials explorer and play with the “Imaginary weight” till you are happy with the fitting.
this is a duplicate case of this one
in your current case, it seems you will need to use more number of fitting coeeficients
if you find the fitting of only real or imaginary part is not good, then you can modify the weight.
Hi, thanks for your kindly reply!
During this time, I am busy with other experiment. Next week, I will focus on simulation again.