Hi all,
I have some questions regarding the Fermi energy.
1. There are actually two Fermi energy after vasp run. One is in the DOSCAR while the other is in OUTCAR file. They are close but not same. Does anyone know why?
2. When I compare the result of SIESTA and VASP for same structure, I find the Fermi energy from VASP is much lower than the result of SIESTA. In SIESTA, I set the label "ElectronicTemperature" to 300K; however, in VASP I don't find the corresponding setting. Can somebody explain this?
Thanks a lot.
About the Fermi energy in VASP
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fzcsydl
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About the Fermi energy in VASP
Last edited by fzcsydl on Tue Jul 05, 2011 6:25 am, edited 1 time in total.
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tlchan
About the Fermi energy in VASP
1. There are actually two Fermi energy after vasp run. One is in the DOSCAR while the other is in OUTCAR file. They are close but not same. Does anyone know why?
I believe it is because DOSCAR averages the results of all the ionic steps for a relaxation/MD run.
2. When I compare the result of SIESTA and VASP for same structure, I find the Fermi energy from VASP is much lower than the result of SIESTA.
With periodic boundary conditions, the Fermi energy is calculated with respect to the average self-consistent potential. If you want to compare the two results, you can compare Fermi energy with respect to some physical energy level, for example VBM for the case of semiconductors.
In SIESTA, I set the label "ElectronicTemperature" to 300K; however, in VASP I don't find the corresponding setting. Can somebody explain this?
You can set the electronic temperature by SIGMA. You can refer to the smearing section in the VASP manual for details.
Last edited by tlchan on Wed Jul 06, 2011 3:46 pm, edited 1 time in total.