Point defects in the 1$T^{\prime }$ and 2$H$ phases of single-layer MoS${}_2$: A comparative first-principles study

Abstract

The metastable 1$T^{\prime }$ phase of layered transition metal dichalcogenides has recently attracted considerable interest due to electronic properties, possible topological electronic phases and catalytic activity. We report a comprehensive theoretical investigation of intrinsic point defects in the 1$T^{\prime }$ crystalline phase of single-layer molybdenum disulfide (1$T^{\prime }$-MoS${}_2$), and provide comparison to the well-studied semiconducting 2$H$ phase. Based on density functional theory calculations, we explore a large number of configurations of vacancy, adatom and antisite defects and analyse their atomic structure, thermodynamic stability, electronic and magnetic properties. The emerging picture suggests that, under thermodynamic equilibrium, 1$T^{\prime }$-MoS${}_2$ is more prone to hosting lattice imperfections than the 2$H$ phase. More specifically, our findings reveal that the S atoms that are closer to the Mo atomic plane are the most reactive sites. Similarly to the 2$H$ phase, S vacancies and adatoms in 1$T^{\prime }$-MoS${}_2$ are very likely to occur while Mo adatoms and antisites induce local magnetic moments. Contrary to the 2$H$ phase, Mo vacancies in 1$T^{\prime }$-MoS${}_2$ are expected to be an abundant defect due to the structural relaxation that plays a major role in lowering the defect formation energy. Overall, our study predicts that the realization of high-quality flakes of 1$T^{\prime }$-MoS${}_2$ should be carried out under very careful laboratory conditions but at the same time the facile defects introduction can be exploited to tailor physical and chemical properties of this polymorph.

11 pages, 10 figures

References in corpus (8)

• Electric Field Effect in Atomically Thin Carbon Films
• Two Dimensional Atomic Crystals
• Quantum Spin Hall Effect and Topological Field Effect Transistor in Two-Dimensional Transition Metal Dichalcogenides
• Two-dimensional transition metal dichalcogenides under electron irradiation: defect production and doping
• Magnetism in MoS2 induced by MeV proton irradiation
• Defect Tolerant Monolayer Transition Metal Dichalcogenides
• Point Defects and Grain Boundaries in Rotationally Commensurate MoS2 on Epitaxial Graphene
• Highly-Oriented Atomically Thin Ambipolar MoSe${}_2$ Grown by Molecular Beam Epitaxy

Cited by in corpus (9)

• MoSSe Janus monolayer as a promising two dimensional material for NO2 and NO gas sensor applications
• Charge-density-wave phase, mottness and ferromagnetism in monolayer $1T$-NbSe${}_2$
• Magnetic exchange interactions in monolayer CrI${}_3$ from many-body wavefunction calculations
• Atomic-scale defects in the two-dimensional ferromagnet CrI${}_3$ from first principles
• Composition Dependence of the Charge Driven Phase Transition in Group-VI Transition Metal Dichalcogenides
• Atomistic $T$-matrix theory of disordered 2D materials: Bound states, spectral properties, quasiparticle scattering, and transport
• Single-layer $1T^{\prime }$-MoS${}_2$ under electron irradiation from $ab$ $initio$ molecular dynamics
• Strain induced effects on the electronic and phononic properties of 2H and 1T${}^{\prime }$ monolayer MoS${}_2$
• Panoply of Ni-Doping-Induced Reconstructions, Electronic Phases, and Ferroelectricity in 1T-MoS${}_2$