LDAUTYPE: Difference between revisions
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Description: {{TAG|LDAUTYPE}} specifies the DFT+U variant that will be used. | Description: {{TAG|LDAUTYPE}} specifies the DFT+U variant that will be used. | ||
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Three variants of the DFT+U approach are available in VASP | Three variants of the DFT+U approach are available in VASP (a brief overview is given [[DFT+U: formalism|here]]): | ||
*{{TAG|LDAUTYPE}}=1: The rotationally invariant DFT+U introduced by Liechtenstein ''et al.''{{cite|liechtenstein:prb:95}} | *{{TAG|LDAUTYPE}}=1: The rotationally invariant DFT+U introduced by Liechtenstein ''et al.''{{cite|liechtenstein:prb:95}} | ||
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'''Warning''': it is important to be aware of the fact that when using the DFT+U, in general the total energy will depend on the parameters <math>U</math> and <math>J</math> ({{TAG|LDAUU}} and {{TAG|LDAUJ}}, respectively). It is therefore not meaningful to compare the total energies resulting from calculations with different <math>U</math> and/or <math>J</math>, or <math>U-J</math> and in case of Dudarev's approach ({{TAG|LDAUTYPE}}=2). | '''Warning''': it is important to be aware of the fact that when using the DFT+U, in general the total energy will depend on the parameters <math>U</math> and <math>J</math> ({{TAG|LDAUU}} and {{TAG|LDAUJ}}, respectively). It is therefore not meaningful to compare the total energies resulting from calculations with different <math>U</math> and/or <math>J</math>, or <math>U-J</math> and in case of Dudarev's approach ({{TAG|LDAUTYPE}}=2). | ||
'''Note on | '''Note on band structure calculation''': the {{FILE|CHGCAR}} file contains only information up to angular momentum quantum number <math>l</math>={{TAG|LMAXMIX}} for the [[LDAUTYPE#occmat|on-site PAW occupancy matrices]]. When the {{FILE|CHGCAR}} file is read and kept fixed in the course of the calculations ({{TAG|ICHARG}}=11), the results will be necessarily not identical to a self-consistent run. The deviations are often large for DFT+U calculations. For the calculation of band structures within the DFT+U approach, it is hence strictly required to increase {{TAG|LMAXMIX}} to 4 (<math>d</math> elements) and 6 (<math>f</math> elements). | ||
== Related tags and articles == | == Related tags and articles == | ||
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{{TAG|LDAUJ}}, | {{TAG|LDAUJ}}, | ||
{{TAG|LDAUPRINT}}, | {{TAG|LDAUPRINT}}, | ||
{{TAG|LMAXMIX}} | {{TAG|LMAXMIX}}, | ||
{{TAG|DFT+U: formalism}} | |||
{{sc|LDAUTYPE|Examples|Examples that use this tag}} | {{sc|LDAUTYPE|Examples|Examples that use this tag}} | ||
Revision as of 13:03, 11 April 2022
LDAUTYPE = 1 | 2 | 4
Default: LDAUTYPE = 2
Description: LDAUTYPE specifies the DFT+U variant that will be used.
Three variants of the DFT+U approach are available in VASP (a brief overview is given here):
- LDAUTYPE=2: The simplified (rotationally invariant) approach to the DFT+U, introduced by Dudarev et al.[2]
- This flavour of DFT+U is of the following form:
Warning: it is important to be aware of the fact that when using the DFT+U, in general the total energy will depend on the parameters and (LDAUU and LDAUJ, respectively). It is therefore not meaningful to compare the total energies resulting from calculations with different and/or , or and in case of Dudarev's approach (LDAUTYPE=2).
Note on band structure calculation: the CHGCAR file contains only information up to angular momentum quantum number =LMAXMIX for the on-site PAW occupancy matrices. When the CHGCAR file is read and kept fixed in the course of the calculations (ICHARG=11), the results will be necessarily not identical to a self-consistent run. The deviations are often large for DFT+U calculations. For the calculation of band structures within the DFT+U approach, it is hence strictly required to increase LMAXMIX to 4 ( elements) and 6 ( elements).
Related tags and articles
LDAU, LDAUL, LDAUU, LDAUJ, LDAUPRINT, LMAXMIX, DFT+U: formalism