Enhanced Spin-Flip Scattering by Surface Roughness in WS$_2$ and MoS$_2$ Armchair Nanoribbons

TL;DR

This study investigates how surface roughness, such as ripples, increases spin-flip scattering in MoS$_2$ and WS$_2$ nanoribbons, impacting spin transport and device design.

Contribution

It demonstrates that out-of-plane deformations significantly enhance spin-flip scattering, providing insights for spintronic device engineering using transition metal dichalcogenides.

Findings

Surface roughness increases spin-flip scattering rates.

Transmission and conductance decrease with surface roughness.

Surface deformations significantly impact spin transport properties.

Abstract

The band structures of single-layer MoS$_2$ and WS$_2$ present a coupling between spin and valley degrees of freedom that suppresses spin-flip scattering and spin dephasing. Here we show that out-of-plane deformations, such as corrugations or ripples, enhance spin-flip scattering in armchair MoS$_2$ and WS$_2$ nanoribbons. Spin transport in the presence of surface roughness is systematically investigated, employing the non-equilibrium Green's function method along with the tight-binding approximation. Both transmission and conductance have been calculated as a function of surface roughness. Our results indicate that the spin-flip rate, usually neglected in flat pristine samples, increases significantly with the surface roughness amplitude. These results are important for the design and fabrication of transition metal dichalcogenides based spintronic devices.