ZrS2

[naomi]

Hey guys
I am trying to simulate ZrS2 monolayer. Actually, I tried many times last week to get its band structure.

Bandstructure of 1*1*2 is different with 2*2*1. My question is how I am able to get same band structure?

I used GGA/PBE/DZP with ecut off 75Hartree and sampling 60.60.1 for my calculation.

Please look at my attached files and let me know what's wrong with my results.


Thanks in advanced.

[Anders Blom]

What do you mean by "same"? If you make a supercell, the band structure looks different but that's because the Brillouin zone also changes when you make the supercell.

[naomi]

Dear Anders,

From what I have seen from ZrS2 bandstructure, Does it make sense that Conduction and Valance band  Value of 1.1.2 , 2.2.2 are different alot?  You know I am surprised with my results because I saw bandgap value of 1.1.2 , 2.2.2 is totally different and also extra subband at Conduction band when I simulate 2.2.2? Why? Help  me plz.

also if you look at https://www.researchgate.net/publication/279865763_Semiconductor-to-metal_phase_transition_in_monolayer_ZrS2_GGAU_study , you will see reported bandgap is totally different with my simulation(However I follow their structure to simulate ZrS2)


if you need more information to help me how I figure out my problems please let me know,
Thanks

[Anders Blom]

So you also included GGA+U as they did in the paper?

What do you mean by "Conduction and Valance band  Value"? Yes, if you make the cell 2x larger the band structure will look very different, as I said, it's expected because of Brillouin zone folding.

[naomi]

actually, I have added U to get similar GGA+U but I haven't get the same result. First, I am trying to understand bandstructure difference without U.

Unknown point left for me  is that I simulate 1.1.2 everything looks Ok (not same but similar subband structure with reported bandstructure, I know affect of U) but when I simulate 2.2.2 I get extra 2subband at conduction band and valence band locate at lower position than 1.1.2. Why?

Please Look at my picture. You will see extra subband and the difference between them, I am trying to understand why extra subband ?what effect on 2.2.2 structure to get different band structure?

Thanks

[Anders Blom]

Brillouin zone folding

[naomi]

Thx