Please find the band gaps

Dear Merve Özcan

I think that you calculated band structure for unitcell in case of instrinsic RbSnF3 and for supercell in case of doped RbSnF3. Because, to add doped atoms to structure and control its percentage, we have to create supercell. From your graphs, your supercell size (for doped RbSnF3) should be 2x2x2 if I am not mistaken. You cannot compare band structure of unitcell and supercell directly. Because, supercell and unitcell has different brilloun zone (It is called folded band structure). If you want to compare band structure of supercell (doped atom included) and unticell (instrinsic), you have to unfold the band structure of supercell. Another simpler way is that calculate the band structure for doped and undoped structure with the same size of supercell. If you don't understand my idea or need another help, just write me.

Jasurbek Gulomov

Jasurbek Gulomov many thanks for your reply. Yes, one of them is unit cell (RbSnF3) and the another supercell (RbSn1-xInx F3) with 2x2x2 (8 times).

Yes, i agree with you, because its doped calculation. But I didnt see any shift in the band gap for doping calculation. I mean that the direct/indirect band gap can shifted in the Brillouin Zone in the doping calculation.

Merve Özcan I recommend you this way. First, just calculate band structure for supercell (undoped RbSnF3) with size of 2x2x2 and compare it with doped one. You can see that thery is shift or not in brilloun zone. If there is shift, you cannot take these high simmetry points as shift. To find exact shift, you have to unfold band structure of doped structure and compare it with band structure of unitcell. It will show exact shift. In this case, I think that there is not direct/indirect shift according to your graphs.

Are you using from Quantum Esrpresso?

Jasurbek Gulomov

Jasurbek Gulomov yes i will calculate the supercell of RbSnF3. I will compare the supercell with and without doping.

Jasurbek Gulomov Yes i am using Quantum espresso code.