Electronic structure evolution of the magnetic Weyl semimetal Co$_3$Sn$_2$S$_2$ with hole and electron doping

TL;DR

This study investigates how the electronic structure of the magnetic Weyl semimetal Co$_3$Sn$_2$S$_2$ changes with hole and electron doping, revealing shifts in bands and the limitations of DFT in modeling local impurity effects.

Contribution

It provides direct ARPES observations of doping-induced electronic structure evolution and compares experimental results with DFT calculations, highlighting the importance of local effects.

Findings

Doping causes observable shifts in electronic bands.

DFT reproduces In doping effects well but not Fe/Ni.

Local impurity effects are significant in Fe and Ni doping.

Abstract

Co$_3$Sn$_2$S$_2$ has been established as a prototype of magnetic Weyl semimetal, exhibiting a ''giant'' anomalous Hall effect in its ferromagnetic phase. An attractive feature of this material is that Weyl points lie close to Fermi level, so that one can expect a high reactivity of the topological properties to hole or electron doping. We present here a direct observation with Angle Resolved Photoemission Spectroscopy of the evolution of the electronic structure under different types of substitutions : In for Sn (hole doping outside the kagome Co plane), Fe for Co (hole doping inside the kagome Co plane) and Ni for Co (electron doping inside the kagome Co plane). We observe clear shifts of selected bands, which are due both to doping and to the reduction of the magnetic splitting by doping. We discriminate between the two by studying the temperature evolution from ferromagnetic to paramagnetic state. We discuss these shifts with the help of DFT calculations using the Virtual Crystal Approximation. We find that these calculations reproduce rather well the evolution with In, but largely fail to capture the effect of Fe and Ni, where local behavior at the impurity site plays an important role.