[Pw_forum] weighted sum over k-points

[Lorenzo Paulatto]

On 8 March 2013 17:13, vikan manmathan <vikanmanmathan1 at gmail.com> wrote:
> hi,
> i was expected that, the weighted sum over k-points in the IBZ has to be 1.
> but, i am getting always 2, while i use Monkhorst and Pack
> k point mesh, irrespective of crystal system.
> i am using even no of k-points, and shifted mesh, like 4 4 4 1 1 1.
> can any one tell me why this is so?

If you do a calculation without spin (this is the default) than each
wavefunction can hole up to 2 electrons: one spin up and one spin
down. Anyway, it is just a convention: the weight could be normalized
to 1 and the factor 2 of spin degeneracy put somewhere else.

bests

-- 
Dr. Lorenzo Paulatto
IdR @ IMPMC -- CNRS & Université Paris 6
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