Giant orbit-to-charge conversion induced via the inverse orbital Hall effect

TL;DR

This paper demonstrates a significant enhancement in orbit-to-charge conversion in heterostructures due to the inverse orbital Hall effect, revealing a universal mechanism across transition metals and advancing spin-orbitronics.

Contribution

It introduces the role of the inverse orbital Hall effect in orbit-to-charge conversion and shows its universality across various transition metals.

Findings

Charge current signal increases nearly tenfold with Ru layer.

Inverse orbital Hall effect is the main contributor to the enhancement.

Universal enhancement observed with different transition metals.

Abstract

We investigate the orbit-to-charge conversion in YIG/Pt/nonmagnetic material (NM) trilayer heterostructures. With the additional Ru layer on the top of YIG/Pt stacks, the charge current signal increases nearly an order of magnitude in both longitudinal spin Seebeck effect (SSE) and spin pumping (SP) measurements. Through thickness dependence studies of the Ru metal layer and theoretical model, we quantitatively clarify different contributions of the increased SSE signal that mainly comes from the inverse orbital Hall effect (IOHE) of Ru, and partially comes from the orbital sink effect in the Ru layer. A similar enhancement of SSE(SP) signals is also observed when Ru is replaced by other materials (Ta, W, and Cu), implying the universality of the IOHE in transition metals. Our findings not only suggest a more efficient generation of the charge current via the orbital angular moment channel but also provides crucial insights into the interplay among charge, spin, and orbit.