Scalar Spin Chirality induced Quantum Anomalous Hall effects

ORAL

Abstract

The quantum anomalous Hall effect(QAHE) is one of the major signature of topological matter. While conventional QAHE originates from spin-orbit coupling, scalar spin chirality(SSC) is another candidate for the emergence of non-trivial QAHE, yet SSC dominant regime is still ongoing topic. In this work, we investigate competition between explicit SSC and hopping on the decorated honeycomb lattice. By analysis of weak and strong SSC limits, we find the system exhibits quantum phase transition from Chern insulator to antiferromagnetic SSC phase. We discuss the crossover between these regimes, with the phase diagram and spin correlations, offering a new perspective on SSC-driven topological transport.

*The quantum anomalous Hall (QAH) effect has been one of the most intriguing topics in modern condensed matter physics, and its microscopic origins continue to be actively explored. While ferromagnetic ordering has been regarded as a primary source of the QAH effect, several recent studies have reported systems exhibiting quantized Hall conductance in the \emph{absence} of long-range ferromagnetism. Among the proposed mechanisms, scalar spin chirality-arising from noncoplanar spin textures-has been suggested as one of key ingredients, yet its microscopic understanding remains incomplete. In this study, we investigate the role of scalar spin chirality in the decorated honeycomb lattice. By analyzing a Hubbard-type model, we derive the effects of scalar spin chirality in both the weak- and strong-coupling limits, obtaining asymptotically exact results. These results allow us to identify possible quantum phase transitions driven by the interplay between electronic correlations and spin chirality, and to construct the plausible phase diagram. Our findings provide an asymptotically exact understanding of scalar spin chirality in correlated systems, offering a new theoretical perspective on the quantum anomalous Hall effect beyond conventional ferromagnetic scenarios.

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Presenters

  • Geonsu Park

    • Korea Adv Inst of Sci & Tech

Authors

  • Geonsu Park

    • Korea Adv Inst of Sci & Tech

  • Eun-Gook Moon

    • Korea Adv Inst of Sci & Tech