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

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

Elucidating the Structural, Electronic, Elastic, and Optical Properties of Bulk and Monolayer MoS2 Transition-Metal Dichalcogenides: A DFT Approach

“…Using this method, which considers the core and valence electrons to be self-consistent in a full-potential treatment, the authors reported the energy band gaps of 1.23 and 1.7 eV for MoS 2 bulk and monolayer, respectively. In another interesting work, Gyan et al 16 studied MoS 2 energy band gaps by considering in their approach the plane-wave pseudopotential approximation within the LDA method and spin–orbit coupling within the generalized gradient approximation (GGA) method. The authors reported an indirect energy band gap in the range of 1.17–1.71 eV for bulk system and 1.6–1.71 eV for monolayer.…”

Novel Braceletlike BiSbX3 (X = S, Se) Monolayers with an In-Plane Negative Poisson’s Ratio and Anisotropic Photoelectric Properties

“…In addition, similar band splitting can also be observed at the PBE level, as presented in Figure S5. This distinct band splitting suggests that BiSbX 3 (X = S, Se) monolayers may have potential applications in spintronics and valleytronics . In addition, the band gap values of these two monolayers calculated at different levels are summarized in Table S2.…”

“…This distinct band splitting suggests that BiSbX 3 (X = S, Se) monolayers may have potential applications in spintronics and valleytronics. 58 In addition, the band gap values of these two monolayers calculated at different levels are summarized in Table S2. To further explore the contribution of each element in these two monolayers, their projected band structure and projected density of states (PDOS) calculated at the HSE level with a consideration of the SOC are depicted in Figure 5.…”