Magnetic Interactions in Co₂TeO₆ Insulating System

This lecture covers the theoretical calculations of nearest-neighbor magnetic interactions in an insulating system with two inequivalent Co sites (Co²⁺, Co³⁺). The instructor explains the use of quantum chemistry methods on embedded clusters to obtain these interactions, focusing on many-body methods and real-space multireference configuration interaction. The results of the calculations are presented, including the isotropic Heisenberg term and Dzyaloshinskii-Moriya interaction. The lecture concludes with the mapping of ab initio data onto a model Hamiltonian, showcasing the single-ion anisotropy tensor and the effective spin Hamiltonian.