[Pw_forum] Charge density at any k-point in the Brillouin zone

[Lorenzo Paulatto]

On 05/02/2013 02:57 PM, koushik pal wrote:
>
>
> Dear PW users,
> I need some clarifications on the input file of pp.x. In the &inputpp 
> namelist, what does the "kpoint" mean?
> To be specific, If I want to visualize the charge density of a 
> particular band ("kband") at any arbitrary k-point in the Brillouin 
> zone (e.g at Gamma (0, 0, 0) and Z(0, 0, 0.5)) what "kpoint" (integer) 
> values should I specify  in each case in the &inputpp namelist?
> Thanks in advance.
Dear Koushik,
the charge density is obtained after a sum over the occupied k-points 
and bands, so you cannot print it for a single k-point.

On the other hand, you can plot the contribution from a specific point 
"k" and band "n", which is the square modulus of the wavefunction 
\psi_{k,n}.

The value of "kpoint" in &inputpp is the index of the k-point, as listed 
in the output of pw.x. If you want to plot a specific point that is not 
in the list you will have to do a nscf calculation first.

best regards

-- 
Dr. Lorenzo Paulatto
IdR @ IMPMC -- CNRS & Université Paris 6
phone: +33 (0)1 44275 084 / skype: paulatz
www:   http://www-int.impmc.upmc.fr/~paulatto/
mail:  23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05