Dopants and grain boundary effects in monolayer MoS₂: a first-principles study

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Chemistry

Background:

• Grain boundaries (GBs) and defects significantly influence the properties of chemical vapor deposited monolayer molybdenum disulfide (MoS2).
• Understanding these effects is crucial for optimizing MoS2 for electronic and spintronic applications.

Purpose of the Study:

• To investigate the electronic and magnetic properties of transition metal (TM) doped MoS2 GBs using first-principles calculations.
• To identify specific TM dopants and GB configurations that lead to favorable magnetic and electronic properties.

Main Methods:

• First-principles calculations based on density functional theory.
• Modeling of experimentally observed 60° tilt GBs in monolayer MoS2 with various atomic configurations.
• Analysis of formation energies and electronic structures of doped and undoped GBs.

Main Results:

• The nonmagnetic 4|8ud GB configuration exhibits the lowest formation energy among the studied GB models.
• Doping with transition metals (V, Cr, Mn, Fe, Co, Ni) significantly lowers GB formation energies compared to pristine MoS2.
• CoMo, MnMo, and Niint in the 4|8ud GB configuration are predicted to be magnetic and energetically favorable.
• Electron coupling between TM dopants and GB atoms induces magnetism and high electron mobility.

Conclusions:

• Defect engineering of MoS2 GBs via transition metal doping is a viable strategy to achieve desired magnetic properties.
• Specific TM dopants (Co, Mn, Ni) in the 4|8ud GB configuration offer a promising route for developing magnetic MoS2 materials.
• This research provides a foundation for the rational design of advanced MoS2-based spintronic devices.