Dear all,
I would ask some information on the Hubbard correction in elk. I'm studying the cerium dioxide, that in the literature is simulated with an Hubbard correction in the range 5-7 eV. While in the literature there is essentially a rigid shift of the 4f states (the main peak in the attached figure), in Elk the Hubbard correction produces a split, with a small peak at lower energy for U=6-7 eV. Somewhere in the discussions I read that the Hubbard correction effect can be different in Elk, is it true? It seems that some cerium 4f states are not influenced by the correction...
first in CeO2 we have the case of an f0 element, means no electrons in the f-states. Thus the U-correction will shift the empty levels upwards, which is also the case from your DOS. What would be interesting to see would be to have a look at the f-states only (partial dos) to see what are really f-states in your plot but I would assume its the double peak. Is this correct?
Regarding the effect of U it should make no difference to other codes. The only technical swtich you can do is to go from FullLocalizedLimit to the MeanField implementation, which only changes how the U affects the states. Could You give a reference to literature what is different from your results with elk?
best
Michael
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Anonymous
-
2020-05-21
Thank you Michael, sorry for the delay, here for example in fig. 2 the 2p-4f gap is an increasing function of the Hubbard correction. In general, I did not found any mention to the second small peak that I found.
I tried to plot the partial density on the Cerium, but is not clear to me how to assign the states to the different lines, I get 16 partial dos for Cerium, with the following relation between the columns
1
2=3=4
5=6=7
8=9
10
11=12=13
14=15=16
The main peak are related to the columns 11-16 while the small unshifted peak is the column 10.
Could you help me in assign the columns to the states?
Dear all,
I would ask some information on the Hubbard correction in elk. I'm studying the cerium dioxide, that in the literature is simulated with an Hubbard correction in the range 5-7 eV. While in the literature there is essentially a rigid shift of the 4f states (the main peak in the attached figure), in Elk the Hubbard correction produces a split, with a small peak at lower energy for U=6-7 eV. Somewhere in the discussions I read that the Hubbard correction effect can be different in Elk, is it true? It seems that some cerium 4f states are not influenced by the correction...
Dear Andrea,
first in CeO2 we have the case of an f0 element, means no electrons in the f-states. Thus the U-correction will shift the empty levels upwards, which is also the case from your DOS. What would be interesting to see would be to have a look at the f-states only (partial dos) to see what are really f-states in your plot but I would assume its the double peak. Is this correct?
Regarding the effect of U it should make no difference to other codes. The only technical swtich you can do is to go from FullLocalizedLimit to the MeanField implementation, which only changes how the U affects the states. Could You give a reference to literature what is different from your results with elk?
best
Michael
Thank you Michael, sorry for the delay, here for example in fig. 2 the 2p-4f gap is an increasing function of the Hubbard correction. In general, I did not found any mention to the second small peak that I found.
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.451.9410&rep=rep1&type=pdf
I tried to plot the partial density on the Cerium, but is not clear to me how to assign the states to the different lines, I get 16 partial dos for Cerium, with the following relation between the columns
1
2=3=4
5=6=7
8=9
10
11=12=13
14=15=16
The main peak are related to the columns 11-16 while the small unshifted peak is the column 10.
Could you help me in assign the columns to the states?
Thanks again,
Andrea
Sorry, I posted as Anonymous...