Large Spontaneous Hall Effects in Chiral Topological Magnets

TL;DR

This paper reports the discovery of large spontaneous Hall effects in non-ferromagnetic topological magnets, including spin liquids and antiferromagnets, linked to magnetic Weyl states, with potential applications due to their unique properties.

Contribution

It identifies and explains the large anomalous Hall effects in chiral topological magnets without significant magnetization, highlighting magnetic Weyl states as the underlying cause.

Findings

Large anomalous Hall effect in Pr2Ir2O7 due to spin ice correlations

Sign change of Hall effect in Mn3Sn and Mn3Ge with small magnetic field variation

Potential for applications owing to Hall effect at room temperature

Abstract

As novel topological phases in correlated electron systems, we have found two examples of non-ferromagnetic states that exhibit a large anomalous Hall effect. One is the chiral spin liquid compound Pr$_{2}$Ir$_{2}$O$_{7}$, which exhibits a spontaneous Hall effect in a spin liquid state due to spin ice correlation. The other is the chiral antiferromagnets Mn$_{3}$Sn and Mn$_{3}$Ge that exhibit a large anomalous Hall effect at room temperature. The latter shows a sign change of the anomalous Hall effect by a small change in the magnetic field by a few 100 G, which should be useful for various applications. We will discuss that the magnetic Weyl metal states are the origin for such a large anomalous Hall effect observed in both the spin liquid and antiferromagnet that possess almost no magnetization.