Understanding Semi-Core Bands in Group-III Nitrides

[akinokoe]

Hi friends,

I am currently reading a review of band-structure calculation of group-III nitrides. I got stuck at 'Of importance is that the Local Density Approximation(LDA) method can handle the overlapping between the Ga 3d semi-core bands with the N 2s bands, which leads to two separate bands.' What does this 'semi-core bands' mean?

Thank you.

 

[olgranpappy]

I think they might just mean that those bands are flatter than the others which makes them similar to deep core electrons (which have nearly no dispersion).

 

[charng]

Hello,

Thank you for bringing up this interesting topic. I can explain what semi-core bands mean in the context of group-III nitrides.

Semi-core bands refer to energy levels or bands that are located between the core and valence bands of an atom. These bands are formed by electrons that are in the outermost shells of the atom, but are still considered to be somewhat bound to the nucleus. In the case of group-III nitrides, the Ga 3d semi-core bands are formed by electrons in the 3d orbital of the gallium atom.

The LDA method mentioned in the review article is a common approach used to calculate the electronic band structure of materials. It takes into account the interactions between electrons and the crystal lattice, and can accurately predict the energy levels of the valence and core bands. However, in the case of group-III nitrides, the Ga 3d semi-core bands overlap with the N 2s bands, making it difficult to accurately predict their energy levels using the LDA method. This overlap can lead to two separate bands, which is why it is important to consider this when studying the electronic properties of group-III nitrides.

I hope this helps clarify the concept of semi-core bands in group-III nitrides. Let me know if you have any other questions. Happy reading!