Improving the dielectric function: Difference between revisions
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* Model-BSE: | * Model-BSE: | ||
:Use a parametrized model<ref name="bokdam:scr:6"/> for the dielectric screening, and DFT eigenenergies moved with a ''scissor'' operator, instead of RPA screening and GW quasiparticle energies. | :Use a parametrized model<ref name="bokdam:scr:6"/> <ref name="liu:bse"> for the dielectric screening, and DFT eigenenergies moved with a ''scissor'' operator, instead of RPA screening and GW quasiparticle energies. | ||
=== Averaging over multiple grids === | === Averaging over multiple grids === | ||
Revision as of 12:04, 17 September 2019
Overview > Dielectric properties of Si using BSE > Improving the dielectric function > Plotting the BSE fatband structure of Si > List of tutorials
Task
Calculate the dielectric function of Si using an averaging over multiple grids or a model-BSE to improve k-sampling in BSE calculations.
Input
Si 5.4300 0.5 0.5 0.0 0.0 0.5 0.5 0.5 0.0 0.5 2 cart 0.00 0.00 0.00 0.25 0.25 0.25
INCAR
- This is the INCAR file for the basic DFT calculation:
System = Si PREC = Normal ; ENCUT = 250.0 ISMEAR = 0 ; SIGMA = 0.01 KPAR = 2 EDIFF = 1.E-8
KPOINTS
Automatic 0 Gamma 4 4 4 0 0 0
Calculation
The calculated spectra can be improved in two ways:
- Averaging over multiple grids:
- Compute N independent dielectric functions using BSE (or any other method), using shifted grids of k-points, and take the average over the results.
- Model-BSE:
- Use a parametrized model[1] Cite error: Closing
</ref>missing for<ref>tag
[2] </references>
Overview > Dielectric properties of Si using BSE > Improving the dielectric function > Plotting the BSE fatband structure of Si > List of tutorials
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- ↑ Cite error: Invalid
<ref>tag; no text was provided for refs namedbokdam:scr:6 - ↑ P.Liu et al., Phys. Rev. Materials 2, 075003 (2018).