Dear colleagues, I'm calculating magnetic anisotropy in YCo5 within GGA+U approach with U-J=0.08 Ry Co d-states, wien2k_19.
To obtain the MAE, K, value the fully self-consistent calculations were executed for in plane and along z-axis magnetic moment orientation. the self-consistency is important for case of GGA+U. Three sets of calculations were executed 1) keep 8 symmetry operation obtained for [100] moment orientation, 2) keep 8 symmetry operations obtained for [110] operations, 3) one E symmetry operation - full BZ integration. The MAE energy is calculated 1) as total energy difference 2) as a difference of band structure energy, EBND. Following results were obtained: >1) 100 - 8 SYM OP: nk=16x16x17-5000: K = 6.53575196338352 meV/fu nk=18x18x20-7000: K = 6.49467997718602 meV/fu nk=16x16x17-5000: K = 15.4869591999841 meV/fu - EBND nk=18x18x20-7000: K = -5.33487200008267 meV/fu - EBND >2) [110] - 8 SYM OP: 16x16x17-5000: K = 6.56594401516486 meV/fu 18x18x20-7000: K = 6.47836000134703 meV/fu 16x16x17-5000: K = 23.350166399905 meV/fu - EBND 18x18x20-7000: K = 24.0896663999706 meV/fu - EBND >3) FBZ - 1 SYM OP: 16x16x17-5000: K = 6.48733603011351 meV/fu 18x18x20-7000: K = 6.45932000479661 meV/fu 16x16x17-5000: K = -23.4508200001642 meV/fu - EBND 18x18x20-7000: K = -14.726882399907 meV/fu - EBND The total energy results for MAE, K, are well converged and insensitive to in-plane magnetization orientation. While, K value calculated from band structure energy, EBND, behaved strange. Expectedly, both ways of K calculation gives close result for regular GGA (the force theorem). Do you know what is source of such irregular EBND difference behavior for GGA+U calculaions? Thank you, German Dr. German D Samolyuk Materials Theory Group Materials Science & Technology Division Oak Ridge National Laboratory Post Office Box 2008 Oak Ridge, TN 37831-6138 (865) 241-5394 (865) 241-3650 (FAX)
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