[Wien] confusion with GGA+U and mbj

[Tran, Fabien]

Hi,



It is recommended (but not mandatory) to do first a GGA calculation before using GGA+U or mBJ. By doing so, the starting electron density for the GGA+U/mBJ SCF iterations may be better than the one from init_lapw (lstart/dstart) in order to reduce the number of iterations and/or to reach the proper ground state.

It may also be a good idea (but again not mandatory) to start a mBJ calculation using the GGA+U electron density.



FT



________________________________
From: Wien <wien-bounces at zeus.theochem.tuwien.ac.at> on behalf of shamik chakrabarti <shamik15041981 at gmail.com>
Sent: Sunday, March 8, 2020 10:09 AM
To: A Mailing list for WIEN2k users
Subject: [Wien] confusion with GGA+U and mbj

Dear Wien2k users,

                           If simulation of a material is to run with GGA+U to get an approximate band gap, then whether GGA+U or GGA has to run as a first step for running mbj?

As user guide says that we have to run a normal SCF prior to mbj, my confusion is whether the normal SCF is to run with GGA or GGA+U if U is mandatory for the material.

Looking forward to your response in this regard.

with regards,

--
Dr. Shamik Chakrabarti
Research Fellow
Department of Physics
Indian Institute of Technology Patna
Bihta-801103
Patna
Bihar, India
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