[QE-users] Query Regarding Band Structure Changes in DFT+U Calculations

[Zimmi Singh]

Dear Developers and Community,

I have observed significant changes in the DFT eigenvalues, particularly in
the positions of the conduction band minimum (CBM), when performing DFT+U
calculations.

In standard DFT calculations, the valence band maximum (VBM) is located at
the Γ point, while the CBM appears between Γ and M. However, upon applying
a Hubbard U correction (U= 2 eV), the conduction band states shift upward
for the spin-down channel and downward for the spin-up channel.
Additionally, the CBM relocates to the K point in the Brillouin zone (see
the attached image). Notably, the overall topology of the CBM is
drastically altered in the DFT+U band structure. Furthermore, the projected
density of states reveals a significant change in occupancy.

I would appreciate any insights into whether such modifications are
expected when incorporating Hubbard U corrections or if there might be an
issue in my calculations.

I sincerely appreciate your time and suggestions.

[image: dft_and_dft+u-min.jpg]

-- 
*Best Regards*
Zimmi Singh

*Research_Scholar *


*Department of Metallurgical and Materials Engineering Indian Institute of
Technology, Kharagpur Kharagpur, India*
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