Separation between Fermi level and CBM/VBM

Concerns issues with computing quasiparticle corrections to the DFT eigenvalues - i.e., the self-energy within the GW approximation (-g n), or considering the Hartree-Fock exchange only (-x)

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Dhanjit
Posts: 41
Joined: Sun Jun 12, 2022 4:18 am
Location: Tezpur, Assam, India

Separation between Fermi level and CBM/VBM

Post by Dhanjit » Fri Jun 06, 2025 3:25 pm

Dear developers,
I have been trying to get values of energy separation between the VBM and CBM with the Fermi energy level. For reference I have attached a schematic of my problem [1.4 eV (CBM-Fermi), 2.0 eV (Fermi-VBM)]. The Fermi energy at QE DFT level is -0.2 eV. Which will remain same for GW as well, right? Now as the ypp shifts the VBM to zero, I get confused with how to get the energy separation at GW level.
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Dhanjit Talukdar
Research Scholar,
Optoelectronics and Photonics Laboratory,
Department of Physics,
Tezpur University, Assam, India

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