First-principles study of novel magnetic properties in strongly correlated materials

Strongly correlated materials exhibit novel magnetism due to the complex coupling between their localized magnetic moments and neighboring electronic/magnetic degrees of freedom. First-principles studies of such materials have been challenging since the widely used density functional theory (DFT) method often fails to capture the strong correlation effect of magnetism. Here, I will show that advanced methods beyond DFT can be successfully applied to various novel magnetic materials capturing the strong correlation effect. First, I will discuss the microscopic origin of a large anomalous spin Hall effect measured in the CoNb₃S₆ compound, where Co ions are intercalated between NbS₂ layers forming a triangular lattice [1]. The Berry curvature calculation based on the DFT+Hartree-Fock band structure can show that the non-coplanar antiferromagnetic spin ordering is crucial to produce such a large anomalous Hall conductivity [2]. Second, I will show that the leading magnetic instability of CoNb₃S₆ obtained from the spin susceptibility and Fermi surface calculations using dynamical mean field theory (DMFT) is consistent with the 3q magnetic structure as expected from the non-coplanar antiferromagnetic ordering [3]. Finally, I will discuss the dynamical fluctuation effect of DMFT on the correlated electronic structure of Na₃Co₂SbO₆ [4], which has been suggested as a possible candidate to realize Kitaev spin liquid [5].

References

[1] N. J. Ghimire et al, Nature Communication 9, 3280 (2018)

[2] H. Park et al, Phys. Rev. Materials 6, 024201 (2022)

[3] H. Park et al, Phys. Rev. B 109, 085110 (2024)

[4] N. Nguyen et al, manuscript in preparation

[5] H. Liu et al, Phys. Rev. Lett. 125, 047201 (2020)