Unconventional transverse transport above and below the magnetic transition temperature in Weyl semimetal EuCd$_2$As$_2$

TL;DR

This study reveals unconventional transverse transport phenomena in EuCd₂As₂ across its magnetic transition, highlighting the role of Berry curvature and the complex interplay between magnetism and topology in this Weyl semimetal.

Contribution

It demonstrates the existence of unconventional anomalous Hall and Nernst effects both above and below the magnetic transition in EuCd₂As₂, a rare observation in a single material.

Findings

Unconventional transverse transport observed above and below magnetic transition

Transport properties differ between antiferromagnetic and paramagnetic phases

EuCd₂As₂ shows potential for hosting various topologically nontrivial phases

Abstract

As exemplified by the growing interest in the quantum anomalous Hall effect, the research on topology as an organizing principle of quantum matter is greatly enriched from the interplay with magnetism. In this vein, we present a combined electrical and thermoelectrical transport study on the magnetic Weyl semimetal EuCd$_2$As$_2$. Unconventional contribution to the anomalous Hall and anomalous Nernst effects were observed both above and below the magnetic transition temperature of EuCd$_2$As$_2$, indicating the existence of significant Berry curvature. EuCd$_2$As$_2$ represents a rare case in which this unconventional transverse transport emerges both above and below the magnetic transition temperature in the same material. The transport properties evolve with temperature and field in the antiferromagnetic phase in a different manner than in the paramagnetic phase, suggesting different mechanisms to their origin. Our results indicate EuCd$_2$As$_2$ is a fertile playground for investigating the interplay between magnetism and topology, and potentially a plethora of topologically nontrivial phases rooted in this interplay.