Electronic Properties of Bulk and Single-Layer MoS2 Using ab Initio DFT: Application of Spin-Orbit Coupling (SOC) Parameters

Michael Gyan ,Francis E Botchway ,Joseph Parbey

doi:10.26565/2312-4334-2020-4-09

Abstract

Two dimensional (2D) materials are currently gaining a lot of interest due to excellent properties that are different from their bulk structures. Single and few-layered of Transition metal dichalcogenides (TMDCs) have a bandgap that ranges between 1-2 eV, which is used for FET devices or any optoelectronic devices. Within TMDCs, a ton of consideration is focused on Molybdenum Disulfide (MoS2) because of its promising band gap-tuning and transition between direct to indirect bandgap properties relies upon its thickness. The density functional theory (DFT) calculations with different functionals and spin-orbit coupling (SOC) parameters were carried out to study the electronic properties of bulk and monolayer MoS2. The addition of SOC brought about a noteworthy change in the profile of the band energy, explicitly the splitting of the valence band maximum (VBM) into two sub-bands. The indirect bandgap in bulk MoS2 ranges from 1.17- 1.71eV and that of the monolayer bandgap was 1.6 – 1.71eV. The calculated parameters were compared to the obtained experimental and theoretical results. The obtained density of states (DOS) can be used in explaining the nature of bandgap in both the bulk and monolayer MoS2. These electronic characteristics are important for applications in material devices and energy-saving applications

Highlights

ELECTRONIC PROPERTIES OF BULK AND SINGLE-LAYER MOS2 USING AB INITIO density functional theory (DFT): APPLICATION OF SPIN-ORBIT COUPLING (SOC) PARAMETERS
Single and few-layered of Transition metal dichalcogenides (TMDCs) have a bandgap that ranges between 1-2 eV, which is used for field-effect transistor (FET) devices or any optoelectronic devices
Within TMDCs, a ton of consideration is focused on Molybdenum Disulfide (MoS2) because of its promising band gap-tuning and transition between direct to indirect bandgap properties relies upon its thickness

Summary

Introduction

ELECTRONIC PROPERTIES OF BULK AND SINGLE-LAYER MOS2 USING AB INITIO DFT: APPLICATION OF SPIN-ORBIT COUPLING (SOC) PARAMETERS. The density functional theory (DFT) calculations with different functionals and spin-orbit coupling (SOC) parameters were carried out to study the electronic properties of bulk and monolayer MoS2. The obtained density of states (DOS) can be used in explaining the nature of bandgap in both the bulk and monolayer MoS2 These electronic characteristics are important for applications in material devices and energysaving applications. Field-effect transistor (FET) based on singlelayer MoS2 using HfO2 as a gate insulator has been experimentally implemented [21] These extraordinary properties have made monolayer MoS2 an interesting material in optoelectronic devices and next-generation FET. The influence of the spin-orbit coupling (SOC) effect on the electronic energy band structure of both monolayer and bulk MoS2 has been calculated in this study. Our results indicate that both bulk and monolayer MoS2 materials are very good candidates for Opto- and spintronic device applications

Methods

Results

Conclusion