Intercorrelated anomalous Hall and spin Hall effect in kagome-lattice Co$_3$Sn$_2$S$_2$-based shandite films

TL;DR

This study demonstrates that Dirac nodes in paramagnetic Co$_3$Sn$_2$S$_2$-based shandite films can generate efficient spin currents via the spin Hall effect at room temperature, revealing an interrelation with the anomalous Hall effect in ferromagnetic states.

Contribution

It uncovers the potential of Dirac nodes in paramagnetic states for spin current generation and links the composition-dependent Hall effects to the ferromagnetic-paramagnetic transition.

Findings

Peak-like spin Hall conductivity at specific compositions.

Intercorrelation between anomalous and spin Hall effects.

Room temperature spin current generation in paramagnetic phase.

Abstract

Magnetic Weyl semimetals (mWSMs) are characterized by linearly dispersive bands with chiral Weyl node pairs associated with broken time reversal symmetry. One of the hallmarks of mWSMs is the emergence of large intrinsic anomalous Hall effect. On heating the mWSM above its Curie temperature, the magnetism vanishes while exchange-split Weyl point pairs collapse into doubly-degenerated gapped Dirac states. Here, we reveal the attractive potential of these Dirac nodes in paramagnetic state for efficient spin current generation at room temperature via the spin Hall effect. Ni and In are introduced to separately substitute Co and Sn in a prototypal mWSM Co$_3$Sn$_2$S$_2$ shandite film and tune the Fermi level. Composition dependence of spin Hall conductivity for paramagnetic shandite at room temperature resembles that of anomalous Hall conductivity for ferromagnetic shandite at low temperature; exhibiting peak-like dependence centering around the Ni-substituted Co$_2$Ni$_1$Sn$_2$S$_2$ and undoped Co$_3$Sn$_2$S$_2$ composition, respectively. The peak shift is consistent with the redistribution of electrons' filling upon crossing the ferromagnetic-paramagnetic transition, suggesting intercorrelation between the two Hall effects. Our findings highlight a novel strategy for the quest of spin Hall materials, guided by the abundant experimental anomalous Hall effect data of ferromagnets in the literature.