[DFTB-Plus-User] DFTB+ density of states against VASP density of states

[Filippo Balzaretti]

Dear all,

I am comparing DFTB+ DOS with VASP DOS and, although the "shapes" are in a good agreement, the DFTB+ one is way higher than that from VASP. This doesn't depend on the system considered, but rather on the way both code are computing the DOS. This is a problem in the moment one is interested in comparing the areas, since any scaling of the curves would be completely arbitrary.

My question is: why are the curves evaluated in DFTB+ much higher? What is the best way to compare them and be sure that the integral is representative of the number of electrons? Unfortunately I couldn't find any documentation on this.

Here an original and scaled version of two DOS for you to understand what I mean. The arbitrary scaling factor for the visual comparison was chosen to let the maximum height of the DFTB curve be the same of that of the DFT curve. The smearing used for both curves is the same (Methfessel-Paxton, order 1, sigma = 0.2).

[cid:c0e5c2d1-3d96-41bb-b551-c8b0f2796f99][cid:15fff45c-e313-4aaa-988c-75fa4327fee5]

Thank you for helping me out!
Best,
Filippo Balzaretti
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