[Wien] Plamon (plasma) in joint/kram

[L. D. Marks]

My main question is whether there is a correction for the effective mass 
built in somewhere here, or not. The UG says "number of ``free`` electrons 
per unit cell assuming bare electron mass (calculated around E_f+/- 10*de 
as defined in input line 4), plasma-frequency". It's not clear if an 
estimate of the effective mass is in there. (If so, it would be nice to 
know what it is so one can do an empirical correction if needed.)

Specific locations:

SRC_joint
line 661 joint,f	plasm2(ip) is plasma frequency for
 			a density (both spins I think). It's not
 			transparent what this density is (few comments).

Used later around line 721 to print out Drude results.

SRC_kram
kram.f	Uses the plasma frequencies (user input) with I assume is 
supposed to have been copied from a previous run of joint (mode 6) and 
adds it to the dielectric constant around line 207.


On Wed, 30 Nov 2005, Fred Nastos wrote:

> On November 30, 2005 01:47 pm, L. D. Marks wrote:
>> From what I can see, joint will (with option 6) calculate a plasmon
>> frequency for an effective mass of one based on the number of electrons,
>> then kram will add this in. This strikes me as strange, probably wrong.
>> Why does one need to do this?
>
> This might be related to the divergent part of the dielectric function.
> For a metal, the Kramers-Kronig relation relating the imaginary part of
> the dielectric function to the real part looks like:
>
> Im[eps(omega)] = sigma/omega - (some principal parts integral)
>
> But I'm not sure exactly what your are referring to when you say "kram will
> add this in".  Can you point out roughly which parts of the code you are
> concerned with?
>
> FN
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-----------------------------------------------
Laurence Marks
Department of Materials Science and Engineering
MSE Rm 2036 Cook Hall
2220 N Campus Drive
Northwestern University
Evanston, IL 60201, USA
Tel: (847) 491-3996 Fax: (847) 491-7820
email: L-marks at northwestern dot edu
http://www.numis.northwestern.edu
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