Fluctuation-driven, topology-stabilized order in a correlated nodal semimetal

TL;DR

This paper uncovers a novel fluctuation-driven magnetic order above the transition temperature in a Weyl semimetal, driven by the interplay of topology and electron correlations, with observable anomalies in transport and neutron scattering.

Contribution

It introduces a new type of magnetic order influenced by topology and fluctuations, extending understanding beyond ground state magnetic orders in topological materials.

Findings

Anomalies in electrical and thermal transport observed.

Neutron scattering confirms magnetic fluctuations.

Coupling of Weyl fermions with magnetic fluctuations explained.

Abstract

The interplay between strong electron correlation and band topology is at the forefront of condensed matter research. As a direct consequence of correlation, magnetism enriches topological phases and also has promising functional applications. However, the influence of topology on magnetism remains unclear, and the main research effort has been limited to ground state magnetic orders. Here we report a novel order above the magnetic transition temperature in magnetic Weyl semimetal (WSM) CeAlGe. Such order shows a number of anomalies in electrical and thermal transport, and neutron scattering measurements. We attribute this order to the coupling of Weyl fermions and magnetic fluctuations originating from a three-dimensional Seiberg-Witten monopole, which qualitatively agrees well with the observations. Our work reveals a prominent role topology may play in tailoring electron correlation beyond ground state ordering, and offers a new avenue to investigate emergent electronic properties in magnetic topological materials.