Fractionalization in spontaneous integer quantum Hall systems

TL;DR

This paper demonstrates that in certain spontaneously formed integer quantum Hall systems, magnetic vortices can carry fractional charge, challenging the common belief that integer quantum Hall systems lack fractional excitations.

Contribution

The study reveals that magnetic Z2 vortices in spontaneously integer quantum Hall systems possess fractional charge, highlighting a novel fractionalization mechanism.

Findings

Magnetic Z2 vortices carry fractional charge.

Integer quantum Hall effect can emerge spontaneously in magnetic systems.

Fractional excitations exist in systems previously thought to lack them.

Abstract

It is widely believed that integer quantum Hall systems do not have fractional excitations. Here we show the converse to be true for a class of systems where integer quantum Hall effect emerges spontaneously due to the interplay of itinerant electrons and noncoplanar magnetic ordering. We show that magnetic $Z_2$ vortices in such systems, whose topological stability is guaranteed by the structure of the order parameter, indeed carry fractional charge.