Multipolar Skyrmion Crystals in Non-Kramers Doublet Systems

TL;DR

This paper explores how bond-dependent electron hoppings in a Kondo lattice model on a triangular lattice stabilize multipolar skyrmion crystals at zero magnetic field, revealing novel topological and Hall effects.

Contribution

It introduces a mechanism for stabilizing multipolar skyrmion crystals via compass-like anisotropy in a Kondo lattice model with non-Kramers doublets.

Findings

Stabilization of multipolar skyrmion crystals at zero field

Fractionalization into meron composites with conserved topological charge

Emergence of a spontaneous Hall response in multipolar phases

Abstract

We study the Kondo lattice model of multipolar magnetic moments interacting with conduction electrons on a triangular lattice. Bond-dependent electron hoppings induce a compass-like anisotropy in the effective Ruderman-Kittel-Kasuya-Yosida interaction between multipolar moments. This unique anisotropy stabilizes multipolar skyrmion crystals at zero magnetic field. In a unit cell, the skyrmion fractionalizes into meron composites subject to the conservation of total topological charge. Diverse multipolar phases in the phase diagram give rise to novel spontaneous Hall response of conduction electrons.