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Hi all,

I calculated optical response of a metal material and use RPA with local field effect to obtain dielectric function. I find the result would change a lot if I set different ElecTemp. I don't understand why the imaginary static dielectric function ( imaginary dielectric function at /Omega=0 ) is not zero when I set ElecTemp = 0.0 eV.
You can check the output with 0K and 300K in attachment.

Best,
Weiqing

Dear Wiking,

this is probably becuase your temperature it is not exactly zero.
From the report you can see: and this happens as the system is metallic.
Anyway the values you get at omega=0 it is also affected by the smearing you used: you can think to low that value.

Note also that, to have a correct description of the metallic behavior it would be appropriate to add the Drude term in your response function: Best,
Daniele

Dear Daniele,

Thanks for you kind reply!

I add Drude term into dielectric function (by DrudeWXd). For q1 (0,0,0), I find that there appears a very large value around /omega=0 in dielectric function. But for finite q, Drude term makes no difference in dielectric function. Is it right?

Best,
Weiqing

Dear Weiqing,
indeed, the Drude term takes into account the term coming for interband transitions in the limit q->0.
For finite q, interband transitions are correctly taken into account in the response function

Best,
Daniele