LDAUTYPE: Difference between revisions
No edit summary |
No edit summary |
||
| Line 27: | Line 27: | ||
{{TAG|LDAUJ}}, | {{TAG|LDAUJ}}, | ||
{{TAG|LDAUPRINT}}, | {{TAG|LDAUPRINT}}, | ||
{{TAG|LMAXMIX | {{TAG|LMAXMIX}} | ||
{{sc|LDAUTYPE|Examples|Examples that use this tag}} | {{sc|LDAUTYPE|Examples|Examples that use this tag}} | ||
Revision as of 15:49, 27 February 2025
LDAUTYPE = 1 | 2 | 4
Default: LDAUTYPE = 2
Description: LDAUTYPE specifies the DFT+U variant that will be used.
The following variants of the DFT+U approach are available:
- LDAUTYPE=2: The simplified (rotationally invariant) approach to DFT+U, introduced by Dudarev et al.[2]
- LDAUTYPE=3: Linear response ansatz of Cococcioni et al. [3] to compute U. See how to calculate U.
Mind: For LDAUTYPE=3, the LDAUU and LDAUJ tags specify the strength of the spherical potential acting on the spin-up and spin-down manifolds, respectively.
A method to estimate the parameters for DFT+U is the constrained-random-phase approximation. Another method is the linear response ansatz with LDAUTYPE=3, mentioned above. On the other hand, in many applications, the DFT+U parameters are used as tuning parameters to fit experimental data.
| Tip: For band-structure calculations, increase LMAXMIX to 4 ([math]\displaystyle{ d }[/math] elements) or 6 ([math]\displaystyle{ f }[/math] elements). |
This is because the CHGCAR file contains only information up to angular momentum quantum number set by 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 necessarily not be identical to a self-consistent run. The deviations are often large for DFT+U calculations.
| Warning: The total energy will depend on the parameters [math]\displaystyle{ U }[/math] (LDAUU) and [math]\displaystyle{ J }[/math] (LDAUJ). It is, therefore, not meaningful to compare the total energies resulting from calculations with different [math]\displaystyle{ U }[/math] and/or [math]\displaystyle{ J }[/math]; or [math]\displaystyle{ U-J }[/math] in the case of Dudarev's approach (LDAUTYPE=2). |
It is possible to use LDAUTYPE=1, 2, and 3 for a non–spin-polarized calculation with ISPIN=1.
Related tags and articles
LDAU, LDAUL, LDAUU, LDAUJ, LDAUPRINT, LMAXMIX