Four-Sublattice Chiral Ordering and Emergent Multipole Degrees of Freedom on a Triangular Lattice

Chiral magnetic orderings in itinerant magnets have recently attracted considerable attention as a source of emergent electromagnetic phenomena such as topological Hall effects and magnetoelectric couplings. In this study, we investigate emergent multipole degrees of freedom arising from chiral magnetic orderings on a two-dimensional triangular lattice. Focusing on a four-sublattice spin configuration characterized by noncoplanar spin textures, we demonstrate that various types of multipoles, such as magnetic dipoles and electric toroidal dipoles, naturally emerge even in the absence of relativistic spin–orbit coupling. By employing a microscopic tight-binding model, we classify the resulting multipole moments and clarify their relationships to the underlying chiral spin texture. We further explore how spin–orbit coupling modifies these multipole characters, leading to additional uniform responses. The results provide a unified framework connecting noncollinear magnetic orderings and emergent multipole phenomena, offering insights into unconventional cross-correlation phenomena in itinerant chiral magnets.