It's the same. The flag LDAU just switches on the "+U" no matter which XC functional you use in the calculation. Whether you use GGA or LDA etc. is solely controlled by the XC functional given in POTCAR (and optionally flags like GGA, LHFCALC etc. -- yes, one could even do hybrids+U with that!).

It's the same. The flag LDAU just switches on the "+U" no matter which XC functional you use in the calculation. Whether you use GGA or LDA etc. is solely controlled by the XC functional given in POTCAR (and optionally flags like GGA, LHFCALC etc. -- yes, one could even do hybrids+U with that!).

Thank you for your replay.

Indeed that is what I do,  I use the POTCAR with the XC functional GGA.  

Please, how can one specify two U for Two different atoms in the same calculation ex "the Hubbard U correction is used with value of 3.5 eV

for both O 2p and Ti 3d states"

Thanks,

Just  as a list of numbers(for L, U, J) separated by white space (for example like:  LDAUL=2 1 ; LDAUU=4.0 3.0 ; LDAUJ=0.  1.) with the order of values corresponding to the order of elements in POTCAR ...

@Jurgen can you tell me please if we have only single type of atoms. how do we set LDAUU and LDAUJ?

Then you give just one single number (in general always as much numbers as types of atoms).

@Jurgen thanks for answer. how do we specify that number?

Mr Mutee Ur Rehman

Refer Materials Project database

https://materialsproject.org

Go to end of the file, click on GGA+U structure optimisation. You can see all input parameters there