# Stability of Weyl points in magnetic half-metallic Heusler compounds

## TL;DR

This study uses relativistic electronic structure calculations to show that the number and position of Weyl points in half-metallic Heusler compounds can be controlled by magnetization orientation, revealing new functionalities unique to these materials.

## Contribution

It demonstrates that magnetization direction can tune Weyl points in half-metallic ferromagnets, a feature not present in other topological materials.

## Key findings

- Number and position of Weyl points depend on magnetization orientation.
- Certain Weyl points remain stable regardless of magnetization rotation.
- Magnetization provides a new control parameter for topological properties.

## Abstract

We employ {\it ab-initio} fully-relativistic electronic structure calculations to study the stability of the Weyl points in the momentum space within the class of the half-metallic ferromagnetic full Heusler materials, by focusing on Co$_2$TiAl as a well-established prototype compound. Here we show that both the number of the Weyl points together with their $k$-space coordinates can be controlled by the orientation of the magnetization. This alternative degree of freedom, which is absent in other topological materials (e.g. in Weyl semimetals), introduces novel functionalities, specific for the class of half-metallic ferromagnets. Of special interest are Weyl points which are preserved irrespectively of any arbitrary rotation of the magnetization axis.