Signature of Hanle Precession in Trilayer MoS2: Theory and Experiment

TL;DR

This paper demonstrates the first electrical injection and detection of spin-polarized carriers in trilayer MoS2, combining experimental measurements with theoretical calculations of Hanle curves to reveal spin dynamics influenced by valley-spin coupling.

Contribution

It provides the first experimental observation of spin transport in trilayer MoS2 and develops a theoretical model for Hanle curves considering intervalley scattering effects.

Findings

Spin lifetime around 110 ps at 30 K.

Hanle curves match theoretical predictions under slow intervalley scattering.

First demonstration of electrical spin detection in trilayer MoS2.

Abstract

Valley-spin coupling in transition-metal dichalcogenides (TMDs) can result in unusual spin transport behaviors under an external magnetic field. Nonlocal resistance measured from 2D materials such as TMDs via electrical Hanle experiments are predicted to exhibit nontrivial features, compared with results from conventional materials due to the presence of intervalley scattering as well as a strong internal spin-orbit field. Here, for the first time, we report the all-electrical injection and non-local detection of spin polarized carriers in trilayer MoS_2 films. We calculate the Hanle curves theoretically when the separation between spin injector and detector is much larger than spin diffusion length, \lamda_s. The experimentally observed curve matches the theoretically-predicted Hanle shape under the regime of slow intervalley scattering. The estimated spin life-time was found to be around 110 ps at 30 K.