Exchange Interactions

Exchange interactions (Js) calculations are the next step in building the model Hamiltonian for the subsequent atomistic spin dynamics calculations. The figure above depicts the exchange interactions taken into account and a comparison of different DFT methods used. As for the magnetocrystalline anisotropy case, the set of (U, J) = (6.5, 1.5) values gives the best approximation for the Js.

The current approach is less computationally expensive compared with previous attempts from Kim et. al. [1], where they used hybrid functionals PBE0, which require computationally expensive calculations, and Wu et.al. [1], where they used extra dipole-dipole interaction to ensure the magnetic ground state is along c-axis.

References

1. Kim, J. W. et al. Successive Magnetic-Field-Induced Transitions and Colossal Magnetoelectric Effect in Ni3TeO6. Phys. Rev. Lett. 115, 137201 (2015).

2. Wu, F., Kan, E., Tian, C. & Whangbo, M.-H. Theoretical Analysis of the Spin Exchange and Magnetic Dipole−Dipole Interactions Leading to the Magnetic Structure of Ni3TeO6. Inorg. Chem. 49, 7545–7548 (2010).