[Pw_forum] london_c6

[Tone Kokalj]

On Fri, 2017-04-28 at 13:47 +0200, Alexandra Davila wrote:
> Dear QE users,
> 
> thanks a lot for the answers.
> The london_c6 variable is for the atomic-type, but in the case I want
> exclude all the metal layers except the first one?? Should I follow
> Prof. Mattioli suggestion, or ?

No not at all, just make two metal atomic-types, one for top layer (say
Me1) and one for other layers (say Me2), but assign the same
psudopotential to both of them. 

Then set londoc_c6(Me1) to value that you want and value london_c6(Me2)
to a very small value, say 1d-8, which is effectively 0.

(I do not recall any more how the londond_c6 is coded currently, but I
know that in the initial version the program assumed a default C6 value
if 0 was specified - this is way I used 1d-8 above - I am too lazy to
look into the code, but I suggest you do it to verify this point)

Best regards, Tone
-- 
J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia 
(tel: +386-1-477-3523 // fax: +386-1-251-9385)