Dear Dr. Oleg Rubel, it is exactly like our case, we have obtained a very small band-gap with GGA (close to zero), but relatively a large value with mBJ. Thanks for you and for Prof. L. Marks
Le lun. 7 sept. 2020 à 17:23, Laurence Marks <laurence.ma...@gmail.com> a écrit : > The evidence I could find is that with LDA/PBE/PBEsol/mBJ Born charges are > slightly too large compared to experiment. Hybrid methods give slightly > (10%) smaller values which seem to be closer to experiment. A caveat is > that I could not find extensive, good experimental data. > > N.B., of course a metal does not have a Born charge... > > --- > 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 > > On Mon, Sep 7, 2020, 10:41 Rubel, Oleg <rub...@mcmaster.ca> wrote: > >> To add to the discussion, here is a tutorial "Born effective charge of >> GaN" from the last WIEN2k workshop ( >> https://urldefense.com/v3/__http://susi.theochem.tuwien.ac.at/events/ws2019/Exercises_19-tot.pdf__;!!Dq0X2DkFhyF93HkjWTBQKhk!GdNcHpBDzmc0bKkfTPuHupsF84fQAHYEE4SpKCD6n0q9kD52LHuFkiYuzaf5sysilMJE0g$ >> ). 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: >> https://urldefense.com/v3/__http://olegrubel.mcmaster__;!!Dq0X2DkFhyF93HkjWTBQKhk!GdNcHpBDzmc0bKkfTPuHupsF84fQAHYEE4SpKCD6n0q9kD52LHuFkiYuzaf5sys_YsgAaQ$ >> >> ________________________________________ >> 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 >> http://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 >> >> https://urldefense.com/v3/__http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien__;!!Dq0X2DkFhyF93HkjWTBQKhk!GdNcHpBDzmc0bKkfTPuHupsF84fQAHYEE4SpKCD6n0q9kD52LHuFkiYuzaf5syuIIoE38g$ >> SEARCH the MAILING-LIST at: >> https://urldefense.com/v3/__http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html__;!!Dq0X2DkFhyF93HkjWTBQKhk!GdNcHpBDzmc0bKkfTPuHupsF84fQAHYEE4SpKCD6n0q9kD52LHuFkiYuzaf5syu4hG8FVw$ >> > _______________________________________________ > 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 >
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