Spin Hall effect in Sr2RuO4 and transition metals (Nb,Ta)

TL;DR

This paper investigates the intrinsic spin and orbital Hall conductivities in multiorbital transition metals, revealing large effects driven by inter-orbital hopping and spin-orbit interactions, with implications for spintronics.

Contribution

It introduces a multiorbital tight-binding model to explain the large spin and orbital Hall conductivities in transition metals, highlighting the role of effective Aharonov-Bohm phases.

Findings

Hall conductivities are much larger than in p-type semiconductors.

The large Hall effects originate from inter-orbital hopping and atomic spin-orbit coupling.

The mechanism is ubiquitous in multiorbital transition metals.

Abstract

We study the intrinsic spin Hall conductivity (SHC) and the $d$-orbital Hall conductivity (OHC) in metallic $d$-electron systems based on the multiorbital tight-binding model. The obtained Hall conductivities are much larger than that in $p$-type semiconductors. The origin of these huge Hall effects is the "effective Aharonov-Bohm phase" induced by the signs of inter-orbital hopping integrals as well as atomic spin-orbit interaction. Huge SHC and OHC due to this mecahnism is ubiquitous in multiorbital transition metals.