Dynamical spin-to-charge conversion on the edge of quantum spin Hall insulator

TL;DR

This paper theoretically demonstrates that the edge of a quantum spin Hall insulator attached to a ferromagnet can efficiently convert spin into charge current, leveraging topological edge states and magnetization dynamics.

Contribution

It introduces a model showing highly efficient spin-to-charge conversion on QSHI edges influenced by magnetic exchange coupling.

Findings

Spin injection is suppressed under large magnetic gap.

Charge current on the edge is maximized due to band topology.

Edge states enable efficient spin-to-charge conversion.

Abstract

We theoretically manifest that the edge of a quantum spin Hall insulator (QSHI), attached to an insulating ferromagnet (FM), can realize a highly efficient spin-to-charge conversion. Based on a one-dimensional QSHI-FM junction, the electron dynamics on the QSHI edge is analyzed, driven by a magnetization dynamics in the FM. Under a large gap opening on the edge from the magnetic exchange coupling, we find that the spin injection into the QSHI edge gets suppressed while the charge current driven on the edge gets maximized, demanded by the band topology of the one-dimensional helical edge states.