Dear Dr. Burak, U is different for AFM and FM states? The problem now is I can not make the U calculation correct. Dr. Matteo is helping me with great patient, but still no luck now.
On Wed, Aug 8, 2012 at 2:49 PM, Burak Himmetoglu <himm0013 at umn.edu> wrote: > Hello Peng, > > One can compute U for the AFM and FM states separately using linear > response. Then, using the calculated U values for each state, you can > recompute the gaps. This approach might resolve the issue. > > Best regards, > > Burak > > On Wed, Aug 8, 2012 at 1:00 PM, Peng Chen <pchen at ion.chem.utk.edu> wrote: > >> Dear All, >> >> According to the experiments, the material's ground state is afm and the >> band gap is ~2.30 eV in 4K. >> In the magnetic field, the spin moments are aligned in the field >> direction (we call it "fm state") and the >> band gap is ~2.34 eV. But from the calculation results, when U>=5 eV, the >> fm spin up gap is less >> than that of afm state which is different from experimental results. (I >> guess we should choose spin >> up gap to represent fm state gap since spin down gap is larger). From the >> calculated gap value, >> U=8 eV is close to experimental results, but the gap in fm state is less. >> Please let me know what >> I can do to improve the results? >> >> >> U afm gap fm spin up fm spin down >> 4 1.49 1.723 1.731 >> 5 1.81 1.77 2.01 >> 6 1.922 1.912 2.273 >> 8 2.265 2.076 2.634 >> >> >> -- >> Best Regards. >> Peng >> >> _______________________________________________ >> Pw_forum mailing list >> Pw_forum at pwscf.org >> http://www.democritos.it/mailman/listinfo/pw_forum >> >> > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > > -- Best Regards. Peng -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120808/5ea0d29b/attachment.htm
