Electronic structures and magnetic properties of MoS2 nanostructures: atomic defects, nanoholes, nanodots and antidots

Abstract

Developing approaches to effectively induce and control the magnetic states is critical to the use of magnetic nanostructures in quantum information devices but is still challenging. Here MoS2-based nanostructures including atomic defects, nanoholes, nanodots and antidots are characterized with spin-polarized density functional theory. The S-vacancy defect is more likely to form than the Mo-vacancy defect due to the form of Mo-Mo metallic bonds. Among different shaped nanoholes and nanodots, triangle ones associated with ferromagnetic characteristic are most energetically favorable, and exhibit unexpected large spin moments that scale linearly with edged length. In particular, S-terminated triangle nanodots show strong spin anisotropy around the Fermi level with a substantial collective characteristic of spin states at edges, enabling it to a desired spin-filtering structure. However, in the antidot, the net spin, coupled order and stability of spin states can be engineered by controlling type and distance of internal nanoholes. Based on the analysis of the spin coupled mechanism, a specific antidot structure, the only S-terminated antidot, was determined to exhibit a large net spin with long-range ferromagnetic coupling above room temperature. Given the recent achievement of graphene- and BN-based nanohole, nanodot and antidot structures, we believe that our calculated results are suitable for experimental verification and implementation opening a new path to explore MoS2-based magnetic nanostructures.

Strain-induced magnetism in MoS2 monolayer with defects

“…Meanwhile, atomic vacancy defects in single-layer MoS 2 14,15 can be easily and even controllably obtained by chemical vapor deposition(CVD) 16 , field evaporation 17,18 and electron irradiation method 19 . However, reports have barely been found on magnetism appearing in MoS 2 with single vacancy 20,21 .…”

Atomic defect states in monolayers of MoS2 and WS2

“…Nevertheless, the sulphur vacancy is the predominant point defect compared to Mo vacancy, regardless of the type of preparation method. 18 The effects of point defects on the electronic structure of LTMDs have also been theoretically studied by several groups using first principles calculations 16,17,[19][20][21][22][23][24][25] and 6-band tight-binding (TB) model 26 . Although, ab initio methods based on density functional theory (DFT) can achieve a good degree of accuracy to describe the electronic structure of pristine LTMD materials, they are limited in their application by the presence of defects in the samples.…”

A simple method for understanding the triangular growth patterns of transition metal dichalcogenide sheets

“…22,23 It has been found that the special triangular nanoflakes of TMDs exhibit many interesting physical and chemical properties. 24 This unique growth pattern inspires people to investigate the underlying reasons. Although density functional theory (DFT) based calculations 25 were carried out to understand the stability of triangular nanoflakes, the effect of edge configurations on the stability has not been studied yet.…”

“…Therefore, the formation energy computed by DFT method in previous work 24 can be calculated now by the simple algebra equations in our Matrix method.…”