DFT+U

[amit_aich]

For Band Gap Calculation, is the DFT + U tags in INCAR correct for ZnO bulk structure ?

############################################
#DFT + U
LDAU = .TRUE.
LDAUTYPE = 1
LDAUL = 2 1
LDAUU = 10. 7.0
LDAUJ = 0.0 0.0
LMAXMIX = 4
LDAUPRINT = 2
LASPH = .TRUE.

[amit_aich]

INCAR,KPOINTS,POSCAR

[ferenc_karsai]

You should apply DFT+U only to d, f electrons. So please set for your case

Code: Select all

LDAUL = 2 -1

Also don't set too high U values, possibly around 5 are a safe value.

Please have a look at our examples for NiO:
https://www.vasp.at/wiki/index.php/Calc ... r_LSDA%2BU ,
https://www.vasp.at/wiki/index.php/NiO_GGA%2BU
and
https://www.vasp.at/wiki/index.php/NiO_LSDA%2BU

[amit_aich]

Thank you for your reply.
I already tried LDAUL = 2 -1 few days ago and also used for lower U values. getting low number (Band gap).

[amit_aich]

Sharing INCAR,KPOINTS,POSCAR. Here I tried for LDAUL = 2 -1 and LDAUU = 5 3. Band Gap = 1.3075. any suggestions?

[ferenc_karsai]

If you want to increase the band gap you should consider using hybrid functionals:
https://www.vasp.at/wiki/index.php/Cate ... unctionals

You can also have a look at this paper for the band gaps using different functionals:
https://pubs.acs.org/doi/10.1021/acs.jpca.7b02882