Quantum Anomalous Hall Effect in Kagome Ice

TL;DR

This paper theoretically demonstrates an anomalous Hall insulator in kagome ice without magnetic long-range order, driven by local spin correlations in pyrochlore spin ice under magnetic field, leading to quantized Hall conductivity.

Contribution

It reveals a new mechanism for the quantum anomalous Hall effect arising from local spin correlations in kagome ice without magnetic ordering.

Findings

Charge gap opens due to kagome-ice spin correlations.

Quantized Hall conductivity observed in the plateau state.

Identification of anomalous Hall insulator regions in phase diagram.

Abstract

An anomalous Hall insulator without magnetic long-range ordering is theoretically reported in the absence of the relativistic spin-orbit coupling. It is realized in itinerant electrons coupled with the Ising spins on a <111> kagome plane of pyrochlore spin ice in applied magnetic field. We find that the kagome-ice type local spin correlation in the magnetization plateau state opens a charge gap without magnetic ordering, which results in quantization of the Hall conductivity. By Monte Carlo simulation, we identify the anomalous Hall insulating region in the magnetic phase diagram, in addition to another anomalous Hall insulator in a fully-saturated state.