I am struggling to figure out the relationship between bandgap value and surface states. To my understanding, when considering the material that includes surface, there would be some surface states in the bandgap or near the VBM/CBM, which often causes the bandgap to decrease.
According to my test and literature research, surface states could decrease the bandgap value by 20%-50%, for example, if the original bandgap value is 1.5eV, when there are surface states, the bandgap could be 1 or 1.2eV.
My question is:
How much would the surface state affect the band gap values, and how could I estimate it?

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    $\begingroup$ I just suggested this on another of your questions, but plot a PDOS and see where the surface states are. $\endgroup$ Jan 16, 2022 at 23:21
  • $\begingroup$ Hi Jack, did Phil's comment help you solve this? Did you figure out the answer over the last ~8 months? It would be nice for this to get out of the unanswered queue! Please update us :) @PhilHasnip do you remember which question it was where you made that suggestion? $\endgroup$ Sep 6, 2022 at 20:14
  • $\begingroup$ @NikeDattani it took a while to find it, I've no idea why I didn't cite it directly back in January... anyway, it's mattermodeling.stackexchange.com/questions/8574/… $\endgroup$ Sep 8, 2022 at 0:02