Basic Electron Band Structure

This isn’t really a news story and I’ll probably be writing a full page on this later, but I wanted to quickly go over the concept of electron bands in materials. It comes down to the concept of bonding and anti bonding pairs or atoms. Imagine a hydrogen atom with a single spin up electron, now if a second hydrogen atom with another spin up electron bonds with it then there are now two energy levels that have to be slightly different from one another. Both electrons will fall to the lowest energy of the two leaving one full orbit and one empty orbit. If there are thousands of atoms, such as in a metal lattice, you get thousands of slightly different energy levels with the lower half filled and the upper half empty.

These levels are so close together they are called bands, the upper is the conductive band and the lower is valence band (conductive to do with conducting and valence to do with bonding). Now for the material to conduct a certain number of electrons must be promoted into the conducting band. The ease of which determines whether the material is an insulator, semiconductor or conductor. Then the entire thing gets more complicated with the addition of fermi levels. Hopefully this will cover the basics that I will go over in more detail when I write the page on the topic. (This was sort of my initial practice write up to check comprehension).


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