[DFTB-Plus-User] Bang gap not matching

[Achyut Subedi]

Hello everyone,

I have been doing DFTB calculation for a system ( COFs ) for the
calculation of band gaps. I optimised the geometry first, and then did DOS
calculation and then Band structure calculation.

In each step I am getting a detailed.out file that contains information
about the Fermi Energy Level. But the value of Fermi energy level is
different in the detailed.out file from step 2 and step 3. What could be
the reason?

Also, from dos_total.dat, I tried to find the band gap by subtracting the
energy level that has 0 DOS around Fermi level but the value of Band gap
that I get from the band structure calculation is completely different with
high order of magnitude. ( 3.9 eV from DOS and 1.93eV from band structure
calculation )
What could be the possible solution to this problem?

Please let me know if any of us need more information in this regard.

-- 
Best Regards
Er. Achyut Subedi
Registered Mechanical Engineer
(IOE, TU, Nepal)
+977-9847703110
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