Band decomposed charge density

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Douasing
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Hi,there are many literatures concered with band decomposed charge density(As an example,see FIG.3 in PHYSICAL REVIEW B 78, 235430 2008).
For condution band,there should not be charges or electrons when the system is in the ground state,but,those literares still show a band decomposed charge density picture,I'm very confused with that.
Douasing
 
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Do you have a link for that figure? I can find it in google, but it's not available for free.
 
Of course. The link is http://journals.aps.org/prb/pdf/10.1103/PhysRevB.78.235430
And the FiG.3 is shown as follows:
upload_2014-12-15_12-34-48.png

FIG. 3. Color online Band decomposed charge density at the Gamma
point for 13,0, 14,0, and 16,0.
 
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In general, the conduction band isn't empty, not even in the ground state, especially in metals. So I don't see a reason as why not to calculate charge density. The pictures you are showing is the electron density $$ |\psi|^2$$ as would result from a single Bloch function or orbital being filled. Obviously, you can plot it irrespective of whether the orbital is filled or not.
 
DrDu said:
In general, the conduction band isn't empty, not even in the ground state, especially in metals. So I don't see a reason as why not to calculate charge density. The pictures you are showing is the electron density $$ |\psi|^2$$ as would result from a single Bloch function or orbital being filled. Obviously, you can plot it irrespective of whether the orbital is filled or not.
In VASP, there is a parameter called NBMOD as follows:
NBMOD=0 : Take all bands to calculate "the charge density", even unoccupied bands are taken into account.
NBMOD=-1: Calculate the "total charge density" as usual. This is the default value if nothing else is given.
What's the difference bewteen "the charge density" and "the total charge density" ?