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Hi,

I am currently conducting a study on the band gap of mixed terminated slabs of CsPbBr3 (CsBr and PbBr2 terminated). However, I have encountered an unexpected result in my calculations. Despite both CsBr and PbBr2 terminated slabs having non-zero band gaps, the mixed terminated slab appears to exhibit a metallic band gap.

Upon examining the band structure diagram, it seems that the gap has shifted downwards. I am unsure if this observation is a result of an error in my calculations or if it is a genuine characteristic of the mixed terminated slab.

I would greatly appreciate your insights on this matter. Could there be a specific reason why the mixed terminated slab shows a zero band gap while the CsBr and PbBr2 terminated slabs have non-zero band gaps? Is it possible that the specific arrangement of atoms in the mixed terminated slab could be causing a change in the electronic structure of the material, leading to an overlap of the valence and conduction bands?

Hello!

I had a look at your input files and I could not find any issues. Unfortunately, I am not expert on surfaces and slabs so I do not know the answer to your question. Since it is a very application-driven issue and not directly a question about VASP I moved this topic into the "From Users for Users" section. Maybe another user has more experience and is willing to share their insight.

All the best,
Andreas Singraber