Dear All,
How does the band gap depend on the number of unit cells? From the computational study, I found that the band gap size of a 2D crystalline solid depends on the number of unit cells. Anyone can explain or can give any reference to read.
Thank you
By how much? Unit cells can disallow certain structural distortions (e.g. in perovskite systems) that can cause a discrepancy in the band gaps when considering larger simulation cells, though typically not by much.
It is around a 2eV difference in the band gap between 1x1x1 and 5x5x1 supercells. However, 4x4x1 retains the band gap as in 1x1x1. Can it be explained and on what basis?
Yes, the band gap of a material can be affected by the number of unit cells. Generally, the larger the number of unit cells, the higher the band gap of the material. For example, the band gap of graphene increases with increasing unit cell size. This is because when particles of the same size are closer together, their wave functions will overlap, thus reducing their energy gab.
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