The role of Coulomb and exchange interaction on the Dzyaloshinskii-Moriya interaction(DMI) in BiFeO3

Ab initio calculations show that the Dzyaloshinskii-Moriya interaction(DMI)and net magnetization per unit cell in BiFeO3 are reduced when U is increasing from 0 to 2.9 eV, and independent of $J$. Interestingly, the DMI is even destroyed as $U$ exceeds a critical value of 2.9 eV. We propose a simple model to explain this phenomenon and present the nature of the rotation of the magnetization corresponding to altered antiferrodistortive distortions under DMI in BiFeO3.