I've been told how to apply the ECR to GaAs{001}(2×4) in my lectures but it makes no sense to me and I don't seem to be able to find any other sources that explain this. (This is a further question on another one posted here .)
Could anyone please tell me how this is done? Or give me some sources on how to apply the ECR?
"This question has been previously asked on the Physics Stack Exchange where it is bountied, but I was told that I should try and post it here as I might be more successful in getting an answer."
This is the explanation I have been given for the following structure:
Count the number of electrons, going down to two of As atoms level with the bottom of the trench and count per unit mesh. There are 8+4 As atoms = 60 valence electrons. There are 6 Ga atoms = 18 electrons. Hence a total of 78 electrons.
Count the bonds that need to be filled :
1. 3 As dimer bonds = 6 e
2. 6 As dangling bonds (2 per dimer) = 12 e
3. Ga dangling bonds (sideways into trench) are empty = 0 e
4. 8 backbonds from top As dimers = 16 e
5. 12 backbonds from Ga to 3rd row As = 24 e
6. 16 backbonds (bulk-like) from 3rd row As to underlying Ga: each takes 5/4 e from As giving 5×16/4 = 20 e
78 electrons for both totals so structure is neutral and should be stable.
I am trying to learn how to do this as I am trying to prove that this is not applicable to the GaAS{001}(2x1) structure, which I believe to be represented like the image below from the help I was given at a previous related question, here.