Topological features in the ferromagnetic Weyl semimetal CeAlSi: Role of domain walls

TL;DR

This study investigates how ferromagnetic domain walls influence the topological electronic properties and transport phenomena in the Weyl semimetal CeAlSi, revealing their crucial role in the material's behavior.

Contribution

It introduces a simplified scattering model of Weyl fermions off domain walls to explain pressure-dependent transport anomalies in CeAlSi.

Findings

Pressure suppresses anomalous and loop Hall effects.

Fermi surface topology is altered by ferromagnetic order.

Domain walls significantly impact transport properties.

Abstract

In the ferromagnetic (FM) Weyl semimetal CeAlSi both space-inversion and time-reversal symmetries are broken. Our quantum oscillation (QO) data indicate that the FM ordering modifies the Fermi surface topology and also leads to an unusual drop in the QO amplitude. In the FM phase, we find a pressure-induced suppression of the anomalous and the loop Hall effects. This cannot be explained based on the electronic band structure or magnetic structure, both of which are nearly pressure independent. Instead, we show that a simplified model describing the scattering of Weyl fermions off FM domain walls can potentially explain the observed topological features. Our study highlights the importance of domain walls for understanding transport in FM Weyl semimetals.