Emergent chiral spin ordering and anomalous Hall effect of kagome lattice at 1/3 filling

Abstract

The study of electronic and magnetic properties of kagome lattice has been an active research area searching for topological phases of matters. In particular, the kagome system with transition metal stannides and etc exhibit interesting anomalous Hall effects driven by ferromagnetic or non-collinear magnetic ordering. In this paper, motivated by these pioneer works, we study strongly correlated spin-orbit coupled electrons in kagome lattice at 1/3 filling. Using both Hartree-Fock approach and effective model analysis, we report quantum phase transitions accompanied with distinct charge and magnetic ordered phases. Especially, for strongly interacting limit, we discover new types of 1(2)-pinned metallic states which are understood by effective localized electron models. Furthermore, when spin-orbit coupling is present, it turns out that such pinned metallic states open a wide region of Chern insulating phase with chiral spin ordering. Thus, quantum anomalous Hall effect is expected with emergent scalar spin chirality. Our theory provides a theoretical platform of strongly interacting kagome metal which is applicable to transition metal stannides.