Spin-states in MoS2 thin-film transistors distinguished by operando electron spin resonance

Naho Tsunetomo,Shohei Iguchi,Małgorzata Wierzbowska,Sinae Heo,Kazuhiro Marumoto,Yutaka Wakayama,Yousang Won,Yesul Jeong,Akiko Ueda

doi:10.1038/s43246-021-00129-y

Abstract

Transition metal dichalcogenide MoS2 is a two-dimensional material, attracting much attention for next-generation applications thanks to rich functionalities stemming from its crystal structure. Many experimental and theoretical works have focused on the spin-orbit interaction which couples the valley and spin degrees of freedom so that the spin-states can be electrically controllable. However, the spin-states of charge carriers and atomic vacancies in devices have not been yet elucidated directly from a microscopic viewpoint. Here, we report the spin-states in thin-film transistors using operando electron spin resonance spectroscopy. We have observed clearly different electron spin resonance signals of the conduction electrons and atomic vacancies, and distinguished the corresponding spin-states from the signals and theoretical calculations, evaluating the gate-voltage dependence and the spin-susceptibility and g-factor temperature dependence. This analysis gives deep insight into the MoS2 magnetism and clearly indicates different spin-scattering mechanisms compared to graphene, which will be useful for improvements of the device characteristics and new applications.

Highlights

Transition metal dichalcogenide MoS2 is a two-dimensional material, attracting much attention for next-generation applications thanks to rich functionalities stemming from its crystal structure
It has been reported that the aforementioned properties are caused by the conduction- and valence-band splitting by the spin–orbit interaction (SOI)[14,15,16], weak electronic localization, and spin–orbit scattering (SOS)[17], discussed from the theoretical and experimental viewpoints
The MoS2 thin film was formed on the sapphire (Al2O3) substrate with a multi-step chemical vapor deposition (CVD) method[32,33]

Summary

Introduction

Transition metal dichalcogenide MoS2 is a two-dimensional material, attracting much attention for next-generation applications thanks to rich functionalities stemming from its crystal structure. We have observed clearly different electron spin resonance signals of the conduction electrons and atomic vacancies, and distinguished the corresponding spin-states from the signals and theoretical calculations, evaluating the gate-voltage dependence and the spin-susceptibility and g-factor temperature dependence. This analysis gives deep insight into the MoS2 magnetism and clearly indicates different spin-scattering mechanisms compared to graphene, which will be useful for improvements of the device characteristics and new applications. Elucidation of the spin states of charge carriers and atomic vacancies is important for understanding the physical properties and functioning of MoS2 transistors

Methods

Results

Conclusion