Spin Hall effect in spin-valley coupled monolayer transition-metal dichalcogenides

TL;DR

This paper investigates the spin Hall effect in monolayer transition-metal dichalcogenides, revealing how scattering mechanisms and doping levels influence the spin Hall conductivity and its sign, with implications for spintronic applications.

Contribution

It provides a detailed analysis of intrinsic and extrinsic contributions to the spin Hall effect in spin-valley coupled monolayers, highlighting the effects of scattering and doping on the spin Hall conductivity.

Findings

Side-jump contribution is comparable to intrinsic with opposite sign.

Intervalley scattering suppresses the side-jump contribution.

Sign change in spin Hall conductivity occurs in heavily hole-doped samples.

Abstract

We study both the intrinsic and extrinsic spin Hall effect in spin-valley coupled monolayers of transition metal dichalcogenides. We find that whereas the skew-scattering contribution is suppressed by the large band gap, the side-jump contribution is comparable to the intrinsic one with opposite sign in the presence of scalar and magnetic scattering. Intervalley scattering tends to suppress the side-jump contribution due to the loss of coherence. By tuning the ratio of intra- to intervalley scattering, the spin Hall conductivity shows a sign change in hole-doped samples. Multiband effect in other doping regime is considered, and it is found that the sign change exists in the heavily hole-doped regime, but not in the electron-doped regime.