To add to the discussion, here is a tutorial "Born effective charge of GaN" from the last WIEN2k workshop (http://susi.theochem.tuwien.ac.at/events/ws2019/Exercises_19-tot.pdf). In this case LDA performs very well. One can try to do TBmBJ to see a difference.
Some systems with a small Eg (for example InN) have Eg = 0 at LDA/GGA level, which created a problem for Berry phase calculations that need a gap. In this case TBmBJ (or DFT+U) would be your best option. I hope it will help Oleg -- Oleg Rubel (PhD, PEng) Department of Materials Science and Engineering McMaster University JHE 359, 1280 Main Street West, Hamilton, Ontario L8S 4L8, Canada Email: rub...@mcmaster.ca Tel: +1-905-525-9140, ext. 24094 Web: http://olegrubel.mcmaster ________________________________________ From: Wien <wien-boun...@zeus.theochem.tuwien.ac.at> on behalf of Laurence Marks <laurence.ma...@gmail.com> Sent: Saturday, September 5, 2020 22:39 To: A Mailing list for WIEN2k users Subject: Re: [Wien] Born effective charge calculation >From what I have found and my tests, either -eece or +U are better as GGA's >overestimate. MBJ does not appear to be better. However, values are often not >that well measured experimentally. --- Prof Laurence Marks "Research is to see what everyone else has seen, and to think what nobody else has thought", Albert Szent-Gyorgi www.numis.northwestern.edu<http://www.numis.northwestern.edu> On Sat, Sep 5, 2020, 19:09 Wien2k User <wien2k.u...@gmail.com<mailto:wien2k.u...@gmail.com>> wrote: Dear Wien2k users, Is it more precise to use mBJ for the calculation of born effective charge or gga is sufficient? (in a case where there is no comparison values) _______________________________________________ Wien mailing list Wien@zeus.theochem.tuwien.ac.at<mailto:Wien@zeus.theochem.tuwien.ac.at> https://urldefense.com/v3/__http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien__;!!Dq0X2DkFhyF93HkjWTBQKhk!Fpbr4B1iYKYmN8y_CnPsog90yWsoj8ABLRarNwPfeAbkXYQflXhH_mF88q2TaPRV6qmLvw$ SEARCH the MAILING-LIST at: https://urldefense.com/v3/__http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html__;!!Dq0X2DkFhyF93HkjWTBQKhk!Fpbr4B1iYKYmN8y_CnPsog90yWsoj8ABLRarNwPfeAbkXYQflXhH_mF88q2TaPT-n2g2Aw$ _______________________________________________ Wien mailing list Wien@zeus.theochem.tuwien.ac.at http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html
