How to enhance anomalous Hall effects in magnetic Weyl semimetal Co$_3$Sn$_2$S$_2$?

TL;DR

This study demonstrates how selective chemical doping in Co$_3$Sn$_2$S$_2$ can significantly enhance its anomalous Hall effects by tuning Berry curvature and impurity scattering, revealing pathways to optimize topological transport properties.

Contribution

The paper introduces a co-chemical doping strategy to maximize anomalous Hall effects in Co$_3$Sn$_2$S$_2$, combining experimental doping techniques with insights into Berry curvature modifications.

Findings

Significant enhancement of AHA (95%) and AHC (190%) at x=0.05 doping in Co$_3$Sn$_{2-x}$In$_x$S$_2$.

Suppression of AHEs observed in hole-co-doped Co$_{3-y}$Fe$_y$Sn$_{2-x}$In$_x$S$_2$.

Unchanged chemical potential in co-doped samples leads to a 116% increase in intrinsic AHC.

Abstract

Large spin-orbit coupling, kagome lattice, nontrivial topological band structure with inverted bands anti-crossings, and Weyl nodes are essential ingredients, ideally required to obtain maximal anomalous Hall effect (AHE) are simultaneously present in Co$_3$Sn$_2$S$_2$. It is a leading platform to show large intrinsic anomalous Hall conductivity (AHC) and giant anomalous Hall angle (AHA) simultaneously at low fields. The giant AHE in Co$_3$Sn$_2$S$_2$ is robust against small-scale doping-related chemical potential changes. In this work, we unveil a selective and co-chemical doping route to maximize AHEs in Co$_3$Sn$_2$S$_2$. To begin with, in Co$_3$Sn$_{2-x}$In$_x$S$_2$, we brought the chemical potential at the hotspot of Berry curvature along with a maximum of asymmetric impurity scattering in high mobility region. As a result at x=0.05, we found a significant enhancement of AHA (95%) and AHC (190%) from the synergistic enhancement of extrinsic and intrinsic mechanisms from modified Berry curvature of gaped nodal lines. Later, with anticipation of further improvements in AHE, we grew hole-co-doped Co$_{3-y}$Fe$_y$Sn$_{2-x}$In$_x$S$_2$ crystals, where we found rather a suppression of AHEs. The role of dopants in giving extrinsic effects or band broadening can be better understood when chemical potential does not change after doping. By simultaneous and equal co-doping with electrons and holes in Co$_{3-y-z}$Fe$_y$Ni$_z$Sn$_2$S$_2$, we kept the chemical potential unchanged. Henceforth, we found a significant enhancement in intrinsic AHC $\sim$116% due to the disorder broadenings in kagome bands