Band decomposed charge density

In summary, there are various literatures discussing band decomposed charge density, such as FIG.3 in PHYSICAL REVIEW B 78, 235430 2008. Despite the fact that the conduction band should not have charges or electrons in the ground state, these literatures still show a band decomposed charge density picture. This has caused confusion for some, as the conduction band is not empty in metals and it is common to calculate charge density regardless of whether the orbital is filled or not. There is a parameter in VASP called NBMOD which allows for the calculation of "the charge density" including unoccupied bands, or "the total charge density" which is the default value and does not include unoccupied bands.
  • #1
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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  • #2
Do you have a link for that figure? I can find it in google, but it's not available for free.
 
  • #3
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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  • #4
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.
 
  • #5
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" ?
 

FAQ: Band decomposed charge density

What is band decomposed charge density?

Band decomposed charge density refers to the distribution of electron density in a material across different energy levels, also known as bands. It is a way to analyze the electronic structure of a material and understand its properties.

Why is band decomposed charge density important?

Band decomposed charge density provides valuable information about the electronic properties of a material, such as its conductivity, magnetism, and optical properties. It is also crucial in understanding the behavior of materials in different conditions, such as under high temperatures or pressures.

How is band decomposed charge density calculated?

Band decomposed charge density is typically calculated using quantum mechanical methods, such as density functional theory (DFT) or the Hartree-Fock method. These methods use mathematical equations and models to describe the behavior of electrons in a material and determine the charge density distribution.

What are some applications of band decomposed charge density?

Band decomposed charge density has various applications in materials science, solid state physics, and chemistry. It is used to study the electronic properties of materials, design new materials with specific properties, and understand the behavior of materials in different environments.

Are there any limitations to band decomposed charge density analysis?

Band decomposed charge density analysis is a powerful tool, but it also has some limitations. It is a theoretical approach and may not always accurately predict the behavior of materials in real-world conditions. Additionally, the accuracy of the results depends on the quality of the input data and the chosen computational method.

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