# Two-orbital effective model for magnetic Weyl semimetal in Kagome-lattice shandite

## TL;DR

This paper develops a simplified two-orbital model for the magnetic Weyl semimetal $
m{{Co}_3{Sn}_2{S}_2}$ on a Kagome lattice, capturing key electronic features and Weyl point configurations consistent with first-principles calculations.

## Contribution

The paper introduces a minimal two-orbital effective model for $
m{{Co}_3{Sn}_2{S}_2}$ that reproduces its electronic structure and Weyl points, including nodal rings with in-plane magnetization.

## Key findings

- Model reproduces Fermi level spectrum and Weyl points.
- Nodal rings appear with in-plane magnetization even with spin-orbit coupling.
- Discussion of magnetic properties of shandite materials.

## Abstract

We construct a two-orbital effective model for a ferromagnetic Kagome-lattice shandite, $\rm{{Co}_3{Sn}_2{S}_2}$, a candidate material of magnetic Weyl semimetals, by considering one $d$ orbital from Co, and one $p$ orbital from interlayer Sn. The energy spectrum near the Fermi level, and the configurations of the Weyl points, computed by using our model, are similar to those obtained by first principle calculations. We show also that nodal rings appear even with spin-orbit coupling when the magnetization points in-plane direction. Additionally, magnetic properties of $\rm{{Co}_3{Sn}_2{S}_2}$ and other shandite materials are discussed.